Check that error is defined in import-account error catch.

ui/app/components/pages/create-account/import-account/json.js

@@ -114,7 +114,7 @@ class JsonImportSubview extends Component {
           setSelectedAddress(firstAddress)
         }
       })
-      .catch(err => displayWarning(err.message || err))
+      .catch(err => err && displayWarning(err.message || err))
   }
 }
 

ui/app/components/pages/create-account/import-account/private-key.js

@@ -104,5 +104,5 @@ PrivateKeyImportView.prototype.createNewKeychain = function () {
         setSelectedAddress(firstAddress)
       }
     })
-    .catch(err => displayWarning(err.message || err))
+    .catch(err => err && displayWarning(err.message || err))
 }