Dale, I can't be sure what your problem is, but I can tell you this: I had a REALLY hard time getting como installed and running correctly on my system. I had lots of correspondence with comeau tech support before it all worked right.
I had the same experience. The helloworld program you use to make sure the compiler is set up right should use the C++ <iostream> header since that stresses setup issues more that one of the C headers.
But once I got helloworld running under Comeau, it was easy to get the Boost build system to run.
I was wondering what build of Comeau people got this working with. I'm using 4.2.45.2b. The <iostream> HelloWorld app, works a treat (in either strict or microsoft mode). The problems I encounter seem to be to do with <cwctype> and Comeau have said they're working on a patch. I'm just wondering how everyone else managed without this. - Dale.