After updating Django subversion to 7549 mod_python was expressing an error- not able to find the django modpython module:
django.core.handlers.modpython

so I finally realized that I changed /home/my/location/DjangoSubversion-XXXX to end in 7549. I had to change the link in /usr/local/lib/python2.5/site-packages/django to the new directory name.

I just learned what

unlink

does- since I had to unlink the old link and make a new one.

For about 2 minutes I thought there was backward incompatible changes in subversion.