This error happens when the Rosetta build system tries to run Python internally to generate additional files used in compilation.  Although we include a complete Python environment with Phenix, Rosetta will probably use the system's Python interpreter (or whatever is defined as the 'python' command).  The error message you see means that this interpreter is completely broken, i.e. something is wrong with your system.  You can confirm this by running a command such as:

python -c "import site"

There's nothing we can do to fix this - you need to consult your local system administrator and/or OS reference manual for assistance/instructions for getting a working Python installed.

(Added this to the FAQ list as well.)

-Nat