diff --git a/app/components/add-proposal/component.js b/app/components/add-proposal/component.js
index aba9926..e7acf1a 100644
--- a/app/components/add-proposal/component.js
+++ b/app/components/add-proposal/component.js
@@ -8,7 +8,7 @@ export default Component.extend({
 
   // Default attributes used by reset
   attributes: {
-    recipientId: null,
+    contributorId: null,
     kind: 'community',
     amount: null,
     description: null,
@@ -22,7 +22,7 @@ export default Component.extend({
 
   contributors: [],
 
-  isValidRecipient: isPresent('recipientId'),
+  isValidRecipient: isPresent('contributorId'),
   isValidAmount: computed('amount', function() {
     return parseInt(this.get('amount'), 10) > 0;
   }),
diff --git a/app/components/add-proposal/template.hbs b/app/components/add-proposal/template.hbs
index c7bb975..4f3cb9f 100644
--- a/app/components/add-proposal/template.hbs
+++ b/app/components/add-proposal/template.hbs
@@ -1,9 +1,9 @@
 <form {{action "submit" on="submit"}}>
   <p>
-    <select required onchange={{action (mut recipientId) value="target.value"}}>
+    <select required onchange={{action (mut contributorId) value="target.value"}}>
       <option value="" selected disabled hidden>Contributor</option>
       {{#each contributors as |contributor|}}
-        <option value={{contributor.id}} selected={{eq recipientId contributor.id}}>{{contributor.github_username}}</option>
+        <option value={{contributor.id}} selected={{eq contributorId contributor.id}}>{{contributor.github_username}}</option>
       {{/each}}
     </select>
   </p>
diff --git a/app/controllers/index.js b/app/controllers/index.js
index aadce1b..764a620 100644
--- a/app/controllers/index.js
+++ b/app/controllers/index.js
@@ -42,10 +42,9 @@ export default Controller.extend({
     this.get('proposals').pushObject(proposal);
   },
 
-  _handleProposalExecuted(proposalId, recipientId, amount) {
-    // TODO: check if proposalId is already a string
+  _handleProposalExecuted(proposalId, contributorId, amount) {
     let proposal = this.get('proposals')
-                       .findBy('id', proposalId.toString());
+                       .findBy('id', proposalId);
 
     if (proposal.get('isExecuted')) {
       Ember.Logger.debug('[index] proposal already executed, not adding from event');
@@ -57,13 +56,13 @@ export default Controller.extend({
     });
 
     this.get('contributors')
-        .findBy('id', recipientId.toString())
+        .findBy('id', contributorId)
         .incrementProperty('balance', amount);
   },
 
   _handleProposalVoted(proposalId, voter, totalVotes) {
     this.get('proposals')
-        .findBy('id', proposalId.toString())
+        .findBy('id', proposalId)
         .setProperties({ 'votesCount': totalVotes });
   },
 
diff --git a/app/controllers/proposals/new.js b/app/controllers/proposals/new.js
index bc1ce67..d6426f1 100644
--- a/app/controllers/proposals/new.js
+++ b/app/controllers/proposals/new.js
@@ -11,7 +11,7 @@ export default Controller.extend({
   actions: {
     save(proposal) {
       // contributorIpfsHash is needed for the proposal ipfs data. I'm not happy to do this here but I think to load all the contributors in addProposal again is a bit too much. I hope we can refactor it later.
-      let contributor = this.get('contributors').findBy('id', proposal.recipientId);
+      let contributor = this.get('contributors').findBy('id', proposal.contributorId);
       proposal.contributorIpfsHash = contributor.get('ipfsHash');
 
       return this.get('kredits').addProposal(proposal)
diff --git a/app/lib/kredits/contracts/operator.js b/app/lib/kredits/contracts/operator.js
index 0ad7f8d..c3e3898 100644
--- a/app/lib/kredits/contracts/operator.js
+++ b/app/lib/kredits/contracts/operator.js
@@ -47,7 +47,7 @@ export default class Operator extends Base {
       .add(json)
       .then((ipfsHashAttr) => {
         let proposal = [
-          proposalAttr.recipientId,
+          proposalAttr.contributorId,
           proposalAttr.amount,
           ipfsHashAttr.ipfsHash,
           ipfsHashAttr.hashFunction,
diff --git a/app/lib/kredits/kredits.js b/app/lib/kredits/kredits.js
index b087371..46a893f 100644
--- a/app/lib/kredits/kredits.js
+++ b/app/lib/kredits/kredits.js
@@ -27,22 +27,44 @@ export default class Kredits {
     this.ipfsConfig = ipfsConfig;
     this.ipfs = new IPFS(ipfsConfig);
 
-    let registryContract = this.initRegistryContract(provider);
+    return this.ipfs._ipfsAPI.id().catch((error) => {
+      throw new Error(`IPFS node not available; config: ${JSON.stringify(ipfsConfig)} - ${error.message}`);
+    }).then(() => {
 
-    let addresses = Object.keys(contracts).reduce((mem, name) => {
-      let contractName = capitalize(name);
-      mem[contractName] = registryContract.functions.getProxyFor(contractName);
-      return mem;
-    }, {});
+      let registryContract = this.initRegistryContract(provider);
 
-    return RSVP.hash(addresses)
-      .then((addresses) => {
-        return new Kredits(provider, signer, addresses);
-      });
+      let addresses = Object.keys(contracts).reduce((mem, name) => {
+        let contractName = capitalize(name);
+        mem[contractName] = registryContract.functions.getProxyFor(contractName).catch((error) => {
+          throw new Error(`Failed to get address for ${contractName} from registry at ${registryContract.address}
+            - correct registry? does it have version entry? - ${error.message}`
+          );
+        });
+        return mem;
+      }, {});
+
+      return RSVP.hash(addresses)
+        .then((addresses) => {
+          return new Kredits(provider, signer, addresses);
+        });
+    });
   }
 
   static initRegistryContract(provider) {
     let address = addresses['Registry'][provider.chainId];
+    if (!address) {
+      throw new Error(`Registry address not found; invalid network?
+        requested network: ${provider.chainId}
+        supported networks: ${Object.keys(addresses['Registry'])}
+      `);
+    }
+    provider.getCode(address).then((code) => {
+      // not sure if we always get the same return value of the code is not available
+      // that's why checking if it is < 5 long
+      if (code === '0x00' || code.length < 5) {
+        throw new Error(`Registry not found at ${address} on network ${provider.chainId}`);
+      }
+    });
     let abi = abis['Registry'];
     console.log('Initialize registry contract:', address, abi, provider);
     return new ethers.Contract(address, abi, provider);
@@ -69,6 +91,9 @@ export default class Kredits {
 
     let contractName = capitalize(name);
     let address = this.addresses[contractName];
+    if (!address || !abis[contractName]) {
+      throw new Error(`Address or ABI not found for ${contractName}`);
+    }
     let contract = new ethers.Contract(address, abis[contractName], this.signer);
     this.contracts[name] = new contracts[contractName](contract);
 
diff --git a/app/lib/kredits/utils/ipfs.js b/app/lib/kredits/utils/ipfs.js
index 5a2a7e4..bc6ccda 100644
--- a/app/lib/kredits/utils/ipfs.js
+++ b/app/lib/kredits/utils/ipfs.js
@@ -51,5 +51,4 @@ export default class IPFS {
     return multihashes.encode(digest, hashData.hashFunction, hashData.hashSize);
   }
 
-
 }
diff --git a/app/models/proposal.js b/app/models/proposal.js
index 7bd376c..b18471f 100644
--- a/app/models/proposal.js
+++ b/app/models/proposal.js
@@ -8,8 +8,8 @@ export default EmberObject.extend({
 
   // Contract
   id: bignumber('idRaw', 'toString'),
-  creatorAddress: null,
-  recipientId: bignumber('recipientIdRaw', 'toString'),
+  creatorAccount: null,
+  contributorId: bignumber('contributorIdRaw', 'toString'),
   amount: bignumber('amountRaw', 'toNumber'),
   votesCount: bignumber('votesCountRaw', 'toNumber'),
   votesNeeded: bignumber('votesNeededRaw', 'toNumber'),
@@ -28,7 +28,7 @@ export default EmberObject.extend({
 
   // Relationships
   // TODO: Optimize it. We don't need to find the contributor every time we add a new one
-  contributor: computed('recipientId', 'kredits.contributors.[]', function() {
-    return this.get('kredits.contributors').findBy('id', this.get('recipientId'));
+  contributor: computed('contributorId', 'kredits.contributors.[]', function() {
+    return this.get('kredits.contributors').findBy('id', this.get('contributorId'));
   })
 });
diff --git a/app/routes/application.js b/app/routes/application.js
index 3119aad..8a6a815 100644
--- a/app/routes/application.js
+++ b/app/routes/application.js
@@ -13,6 +13,8 @@ export default Route.extend({
           transition.retry();
         }
       }
+    }).catch((error) => {
+      console.log('Error initializing Kredits', error);
     });
   },
 
diff --git a/app/utils/cps/bignumber.js b/app/utils/cps/bignumber.js
index 701eed1..f86cab2 100644
--- a/app/utils/cps/bignumber.js
+++ b/app/utils/cps/bignumber.js
@@ -1,4 +1,5 @@
 import computed from 'ember-computed';
+import ethers from 'npm:ethers';
 
 export default function(dependentKey, converterMethod) {
   return computed(dependentKey, {
@@ -6,6 +7,7 @@ export default function(dependentKey, converterMethod) {
       return this.get(dependentKey)[converterMethod]();
     },
     set (key, value) {
+      value = ethers.utils.bigNumberify(value);
       this.set(dependentKey, value);
       return value[converterMethod]();
     }
diff --git a/tests/unit/controllers/index-test.js b/tests/unit/controllers/index-test.js
index fec0ad3..827d256 100644
--- a/tests/unit/controllers/index-test.js
+++ b/tests/unit/controllers/index-test.js
@@ -12,20 +12,12 @@ moduleFor('controller:index', 'Unit | Controller | index', {
 });
 
 let addFixtures = function(controller) {
-  controller.set('model', {
-    contributors: [],
-    proposals: []
-  });
-
   [
     { github_username: "neo", github_uid: "318", balance: 10000 },
     { github_username: "morpheus", github_uid: "843", balance: 15000 },
     { github_username: "trinity", github_uid: "123", balance: 5000 },
     { github_username: "mouse", github_uid: "696", balance: 0 }
   ].forEach(fixture => {
-    // we expect a bignumer but I don't want to add the bignumber dependency here... so this is some hack to return an object that looks good enough for the test
-    let fakeBignumber = function(balance) { return { toNumber: function() { return balance; } }; };
-    fixture.balance = fakeBignumber(fixture.balance);
     controller.get('kredits.contributors').push(Contributor.create(fixture));
   });
 };