Unexpected error during processing: null

[Gulli]

Hi everyone,

I'm getting this error:

org.kie.server.client.KieServicesException: Unexpected HTTP response code when requesting URI 'http://localhost:8080/kie-server/services/rest/server/containers/AS1/tasks/27'! Error code: 500, message: Unexpected error during processing: null
 at org.kie.server.client.impl.AbstractKieServicesClientImpl.createExceptionForUnexpectedResponseCode(AbstractKieServicesClientImpl.java:539)
 at org.kie.server.client.impl.AbstractKieServicesClientImpl.makeHttpGetRequestAndCreateCustomResponse(AbstractKieServicesClientImpl.java:160)
 at org.kie.server.client.impl.UserTaskServicesClientImpl.getTaskInstance(UserTaskServicesClientImpl.java:738)

Now what I've done is this:
 - Created a custom .jar file that has custom tasks
 - I've added this .jar as a dependency to a project
 - Created a workflow using one of these tasks
 - Tried to envoke the workflow through the rest services

jBPM worked fine before introducting this jar. After uploading the .jar I've been getting this error. The strangest thing is though, if I completely uninstall jBPM and get a fresh copy (or do ant clean.demo), I get this error again - even though I don't introduce my custom jar at all. It just does not work. I've tried this on three dev computers.

Anyone have any ideas of whats going on?

Best regards,
Gulli