Nothing can link with gtk on Snow Leopard

Hi, I'm running Mac OS X Snow Leopard. I've done a "sudo cabal install gtk --global" on my system, and it warns me that "file was built for unsupported file format which is not the architecture being linked (i386)". What does this refer to? Subsequently, nothing else _links_ properly with gtk. For example, hp2any-manager (or other tools) all fail during linking with gtk. Am I doing something wrong? Thanks, Mark