That error code is being returned by msdev (the VC6 command-line compiler that VBP invokes to actually perform the build. If the build has successfully completed, you can use the workaround described here:
http://www.kinook.com/Forum/showthre...?threadid=1463.
Otherwise, you would need to open a support incident with Microsoft regarding the problem. You can reproduce the problem outside VBP by checking the 'Display command-line...' option on the Options tab of the Make VC6 action, build again, and then copy/paste the failing msdev call into a Command Prompt and running there.