You don't say which ROM you are using, but this sounds like the daylight savings time related bug in the latest Sprint "leaked" ROM and the custom ROMs based on it. You should be able to fix this issue by flashing to one of the more current ROMs in the Diamond Upgrade subforum, or see this post for a cab that might work for you.
http://forum.ppcgeeks.com/showpost.p...&postcount=773
Good luck!
- Ambrose