xPC Target "Malformed Message"

Hi,
I'm having trouble with xPC Target with simulink in external mode.
The host and target are connected with direct ethernet connection.

The model is configured as a stream of linearly increasing binary values sent to a
UEI PDL-DIO-64 digital I/O card with 12-outputs looped into 12-inputs to test the interface.

The model compiles and uploads though the process produces a number of errors which I can't find any information on.

The reoccuring errors are:

 |'Error: Executing the 'Get Time' command produced the following error:
 |Target PC1: Malformed Message'

 |'Error: Executing the 'Final Upload' command produced the following error:
 |Target PC1: Malformed Message'

 |'Error: Executing the Check data' command produced the following error:
 |Target PC1: Malformed Message'

and a number of warnings:

 |Warning: External Mode Open Protocol SetParam command failed with status 1
 
 |Warning: External Mode Open Protocol Signal Select command failed with status 1

The code seems to run, but the I/O doesn't work.

Any help would be great appreciated, I've searched the web for similar errors/warning but found nothing.

Thanks,
Dan