[modeller_usage] I am having problems to install the MODELLER

Hi, i instaled the modeller 9v2 in Pentium D PC, when trying to twirl software
it presents the following error:

mod9v1 salign_fix_positions.py
Could not find platform independent libraries <prefix>
Could not find platform dependent libraries <exec_prefix>
Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>]
'import site' failed; use -v for traceback

Thanks,
Gustavo G. Pereira

LNLS - Laboratori Nacional deLuz Sincroton - http://www.lnls.br