I already posted the following in the Modules Troubleshooting forum, however I decided it might be a good idea to cross post it since I'm not sure if this is related to the modules themselves (as it happens with every module that doesn't come with Xoops) and this forum seems like it gets a lot more attention.

Hi. I just tried to install the document management system and the iMenu modules and for some reason they aren't showing up in the list of modules I can install. I've done this before and it worked fine. I have the directories containing the modules in the right place and they both are readable/writable by Xoops. I'm getting no error output, so it seems like it's not even seeing the modules. Anyone else out there had this problem? If so, what am I doing wrong?

Nevermind, I figured it out. It had to do with a short perl script I wrote to make backups of XOOPS (and the database) before I made major changes that might break it. It seems I failed to update the value of XOOPS_ROOT_PATH in mainfile.php to point to the new path instead of pointing to the old XOOPS path.