Comment 4 for bug 688138

Dave Gordon (python-bugz) wrote :

Probably down to a change in Python 2.7. Up until 2.6, if you passed a float to a function that was defined as taking an int, the float would automatically be converted, though possibly with a DeprecationWarnng. In 2.7 (and Python 3000) it's now a TypeError. So, you have to put in an explicit conversion to int wherever this occurs.

There are quite a lot of packages affected by this!

Also, in the OP's case it was happening on python 2.6, but only after 2.7 was installed; the traceback shows that "python2.6" is actually using the library modules from 2.7, so it gets the same error.