Here is a list of error codes encountered on running games.

80010002 - Homebrew not KXploited (1.50)/Homebrew attempted to run (1.51/1.52)
8001007B - UMD was removed while booting
800201A8 - Memory Stick was removed while booting game
80020148 - Update file placed in non-update folder/System software must be updated to run demo
80020146 - ? (Appears when exiting SWFPlayer 1.3)
FFFFFED3 - System software must be updated to run UMD

There is also one that ends with AC... it is like "80xxxxAC", but I can't remember the other numbers/letters. If you remember what it was and when it appears, please tell.