ps3 + media server issue with seeing files/directories

hello! i have my ps3 hooked up to my network and it picks up the upnp server that i have. the issue is that the directories are getting all messed up and displaying as 'null'. i can still access them, but now files are not displaying. when i look at the server from other machines, or even the other ps3, all the files and directories are as they should be. is there a db file on the ps3 that can be reset to refresh all the files on the media server? is there somewhere else i can reset this so the ps3 scans the server from scratch? thanks!