Universal binary woes

Chris Rolfe's icon

I'm able to most of my objects as Universal binaries but one is giving me trouble. It builds, but gives the following error in the Max window on when running on PPC:

unable to load object bundle executable
Error loading /Users/chris/myobject.mxo/Contents/MacOS/myobject error code 4, error number 0 (Symbol not found: __stack_chk_fail

Can anyone suggest what's happening?

regards,
Chris