the disk channel uses IOSs, note a cIOS (custom IOS)
download this package here (http://www.mediafire.com/download.php?izvndnndztu)
be sure to update your HBC to v1.06 first before updating
follow the instructions in the read me (in the download) to update to 4.2 (make sure to install ios70 BEFORE the system menu). U dont need to update your shop channel, photo channel etc. if u dont want to
if u have priiloader installed, u will need to reinstall it afterwards
EDIT: i still recommend updating to 4.2 (or 4.1, whatever u want), but modmystuff is right, there was a hardmod bug in the latest rev of priiloader (v0.3b), which causes your problem. I read it occured when disks were INSERTED while in the system menu. A simple solution would be to launch your disk games via tinyload (homebrew app) or neogamma (see my signature). But if u would reinstall a different rev of priiloader it should fix u right up