This is very common, it happened to me too. I thought I was smart but forgot to install the Python development packages on my Linux machine. Normally these packages are named like "python-devel" or "python-dev", and are absolutely necessary to build Python modules and extensions. One possible reason can also be that you are using an embedded version of Python: in this case it would be better to install a standalone Python interpreter, same version as the embedded one, and use it to build the module. After doing that, you should copy the 'clips' subdirectory from its 'site-packages' to your embedded Python 'site-packages': this should, in most cases, allow you to call PyCLIPS from an embedded Python release. I don't know how to link PyCLIPS with Python in a custom build: probably it's quite easy... if anyone finds out how to do it, please give me some information about it.