Dear all, I want to use the program combine.py to subtract two delphi potential maps. I have the most recent stable version of Chimera installed in /usr/local/chimera. Following the documentation, I set the PYTHONPATH variable with setenv PYTHONPATH /usr/local/chimera/share then I try to run the program with /usr/local/chimera/bin/python2.5 /usr/local/chimera/share/VolumeProcessing/combine.py but the result is always: Traceback (most recent call last): File "/usr/local/chimera/share/VolumeProcessing/combine.py", line 12, in <module> from VolumeData import Grid_Data File "/usr/local/chimera/lib/python2.5/site-packages/PIL/__init__.py", line 10, in <module> # File "CHIMERA/share/VolumeData/opendialog.py", line 70, in <module> File "/usr/local/chimera/lib/python2.5/site-packages/PIL/__init__.py", line 72, in <module> File "/usr/local/chimera/lib/python2.5/site-packages/PIL/__init__.py", line 15, in <module> ImportError: No module named _chimera How can I overcome this problem? Thanks in advance, Michele