If you are installing Bugzilla on SuSE Linux, or some other distributions with "paranoid" security options, it is possible that the checksetup.pl script may fail with the error:
cannot chdir(/var/spool/mqueue): Permission denied
This is because your /var/spool/mqueue directory has a mode of drwx------. Type chmod 755 /var/spool/mqueue as root to fix this problem. This will allow any process running on your machine the ability to read the /var/spool/mqueue directory.