Dear Chimera Team, I am working on my own Chimera Extension. After succesful installation of BioPython using Chimera's Python copy, I've encountered another BioPython - related problem, that is also related to the numpy library. I'm trying to import something from the BioPython library, and BioPython is trying to import from numpy. I recieve a following error: RuntimeError: module compiled against API version 8 but this version of numpy is 7 ... File "/home/mateusz/pyry4.4/Modules/Trans/ComponentRepresentation.py", line 6, in <module> from Bio.PDB import PDBParser, PDBIO, NeighborSearch File "/home/mateusz/.local/UCSF-Chimera64-1.8.1/lib/python2.7/site-packages/Bio/PDB/NeighborSearch.py", line 10, in <module> from Bio.KDTree import KDTree File "/home/mateusz/.local/UCSF-Chimera64-1.8.1/lib/python2.7/site-packages/Bio/KDTree/__init__.py", line 10, in <module> from KDTree import KDTree File "/home/mateusz/.local/UCSF-Chimera64-1.8.1/lib/python2.7/site-packages/Bio/KDTree/KDTree.py", line 20, in <module> from Bio.KDTree import _CKDTree <type 'exceptions.ImportError'>: numpy.core.multiarray failed to import I tried to install numpy the same way I installed BioPython (using Chimera's Python copy), but this does not solve the problem. I also tried to import numpy.core.multiarray directly in Chimera's IDLE and it did import. I'm using Chimera 1.8.1 on Ubuntu 12.10 (64 - bit). Is there anything I can do to make it work? Best wishes, Mateusz