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First, I never use Fantastico to install XOOPS any more because it has always screwed something up with me. You are less likely to have headaches doing it the FTP way because you can make sure everything that needs to be done to XOOPS to install properly actually happens. Plus, it installs into a directory like that and I've never liked that, especially if you want to put it in the root directory. But, if you moved it you should only have to change the mainfile.php information in order to have it point somewhere else.
Note: today I moved a site and changing the mainfile info didn't work. I got a blank page. I suggest a search of the forums for an answer for this.
Second, to make everything appear for guest users, you should go into the Group settings and turn on what you want available for them.