Try "PYTHONPATH=/usr/lib/python2.5/site-packages ccsm".
If that works, it means that ccsm is using /usr/local/lib/ptython..... So to fix it, just remove or rename the directory /usr/local/lib/python2.5/site-packages/ccm.
Try "PYTHONPATH= /usr/lib/ python2. 5/site- packages ccsm".
If that works, it means that ccsm is using /usr/local/ lib/ptython. .... So to fix it, just remove or rename the directory /usr/local/ lib/python2. 5/site- packages/ ccm.