I managed to resolve the problem. I was using the pre-built cross compiler that Mark provides for the empeg at http://empeg-hijack.sourceforge.net/ which wasn't working. I have switched to use the cross compiler that Jeff Mock provides at http://www.mock.com/receiver/tools/ for the Receiver which is working fine.

As far as I can see Mark's tool chain should work, there are no Receiver specific steps detailed in Jeff's instructions of how to build your own tool chain, so I don't know why Mark's didn't work on the Receiver kernel. I even checked the versions, both are based on gcc 2.95.2