diff --git a/polling-station/src/main/java/meerkat/pollingstation/ReceiverWebAPI.java b/polling-station/src/main/java/meerkat/pollingstation/ReceiverWebAPI.java
index 7463db7..b396045 100644
--- a/polling-station/src/main/java/meerkat/pollingstation/ReceiverWebAPI.java
+++ b/polling-station/src/main/java/meerkat/pollingstation/ReceiverWebAPI.java
@@ -2,7 +2,9 @@ package meerkat.pollingstation;
 
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.protobuf.BoolValue;
+import meerkat.pollingstation.controller.callbacks.ScanCallback;
 import meerkat.pollingstation.controller.callbacks.ScanDataCallback;
+import meerkat.pollingstation.controller.callbacks.ScanErrorCallback;
 import meerkat.protobuf.PollingStation;
 
 import javax.annotation.PostConstruct;
@@ -28,7 +30,7 @@ public class ReceiverWebAPI implements PollingStationScanner.Producer {
     @Context
     ServletContext servletContext;
 
-    LinkedBlockingQueue<FutureCallback<PollingStation.ScannedData>> callbacks;
+    LinkedBlockingQueue<ScanCallback> callbacks;
 
     /**
      * This method is called by the Jetty engine when instantiating the servlet
@@ -39,7 +41,7 @@ public class ReceiverWebAPI implements PollingStationScanner.Producer {
         Object context = servletContext.getAttribute(ReceiverScanHandler.CALLBACKS_ATTRIBUTE_NAME);
 
         try {
-            callbacks = (LinkedBlockingQueue<FutureCallback<PollingStation.ScannedData>>) context;
+            callbacks = (LinkedBlockingQueue<ScanCallback>) context;
         } catch (ClassCastException e) {
             throw e;
         }
@@ -89,7 +91,7 @@ public class ReceiverWebAPI implements PollingStationScanner.Producer {
 //
 //        }
 
-        ScanDataCallback callback = new ScanDataCallback(errorMsg);
+        ScanErrorCallback callback = new ScanErrorCallback(errorMsg);
 //        scanner.subscribe(callback);
         callbacks.add(callback);
 
diff --git a/polling-station/src/main/java/meerkat/pollingstation/controller/callbacks/ScanErrorCallback.java b/polling-station/src/main/java/meerkat/pollingstation/controller/callbacks/ScanErrorCallback.java
index 8ddb0c6..58aa16e 100644
--- a/polling-station/src/main/java/meerkat/pollingstation/controller/callbacks/ScanErrorCallback.java
+++ b/polling-station/src/main/java/meerkat/pollingstation/controller/callbacks/ScanErrorCallback.java
@@ -8,9 +8,9 @@ import meerkat.protobuf.PollingStation;
  */
 public class ScanErrorCallback extends ScanCallback implements FutureCallback<PollingStation.ErrorMsg> {
 
-    private final String expectedErrorMessage;
+    private final PollingStation.ErrorMsg expectedErrorMessage;
 
-    public ScanErrorCallback(String expectedErrorMessage) {
+    public ScanErrorCallback(PollingStation.ErrorMsg expectedErrorMessage) {
         this.expectedErrorMessage = expectedErrorMessage;
     }