Bonita Error: be_TRT_2 Exception

We are using Bonita Open Solution version 5.6 and we are getting the following exception:

WARNING: Activity will be put in the state FAILED due to: org.ow2.bonita.facade.exception.BonitaWrapperException: org.ow2.bonita.facade.exception.RoleMapperInvocationException: Bonita Error: be_TRT_2Exception caught while executing role mapper: org.ow2.bonita.facade.def.InternalConnectorDefinition@556eafa6

Can anyone offer some help on how I could trace or solve this problem?

Websockets and Bonita

It's possible to use websockects to send information about the state of the workflow to make an interface react?

A process that catches events of 5 participants voting and I wanted to send, when all voted, a typified message through a websocket that is listening on the other application (back-end or front-end).

The interface and application referred above aren't the default Bonita portal.

Anyone has already tried this?
Is there any alternative on the API that you know of?