IIRC, the documentation of bugzilla does say that in the directory directive to use +FollowSymLinks, but I can't be totally sure as when I set up bugzilla to test it, I installed the bugzilla directory directly in the document root. It still didn't work for me until i changed all the .cgi files' permissions to 755. it seemed to me that running checksetup.pl the last time really does make the files pretty restrictive. Anyhoo, I don't really know much about bugzilla, but I didn't want your post to feel lonely.
Hope you get it sorted out.
Optional: If Bugzilla does not actually reside in the webspace directory, but instead has been symbolically linked there, you will need to add the following to the Options line of the Bugzilla <Directory> directive (the same one as in the step above):
Without this directive, Apache will not follow symbolic links to places outside its own directory structure, and you will be unable to run Bugzilla.