Manveru wrote:
Python 3.0 is not backward compatible with 2.x series. I do not know how it is on Mac, but I think LyX has it's own python interpreter bundled.
No, on Mac python is not bundled with LyX, since it is already bundled with Mac OS X. The only way I see to fix this is to install python_select and select Apple's python (or another complete 2.x installation) as the default python.
HTH, Konrad