In /app_home??? That's really weird...
If you have a backup of a PS2 game you can try to copy it to your USB/internal HDD in your games folder and try to mount it.
Well... even if it doesn't work at the moment, may be in the future with some proper updates to the payload or using dev_flash off a usb stick may get out favorite PS2 games to run... May be the XMB xml file needs some tweeks... there was a tool for this in the 'news' thread.
Check this thread --> http://www.ps3news.com/forums/ps3-ha...de-113851.html