Warning: Changing your PSN email or password via the PS3's XMB account management tool will corrupt your save files! Sadly, PlayStation 3 Firmware Update 2.53 does NOT resolve this issue.
There is a large thread (linked above) over at the PlayStation forums regarding error 80022d11 (save file created by another user).
Once this occurs, trying to load a save file for a game that supports trophies will give you the option to either start over (wipe the save file) or sync trophies (which fails). At this point trophies will no longer work and save game files for any game that supports trophies will no longer load.
The only work around at this point is to delete your PS3 user account (not to be confused with your PSN user account) and create a new one (which you can link to your existing PSN account).
Once this is done your trophies will sync, but you will lose all your saved games. If you try to restore any saved games you made before doing this, the error will occur again.
The problem appears to be triggered if the user changes his/her email address or password using the XMB account management tools. So until Sony fixes this problem, users should not change their PSN email address or password. More PlayStation 3 News...