Such exceptions need to be handled separately when catching the generic
Exception class under Python 2.4 or they get gobbled up by the generic exception
handling.
Now using setuptools 1.4.2 with Python 2.4 & 2.5, and using setuptools 3.3 with
later Python versions. This should help avoid installation issues in different
exotic use cases that were once not being handled by setuptools but have since
been corrected.