Ever since yesterday, whenever I do a battery pull and I unlock my phone I get the following message: Uncaught exception: java.lang.NullPointerException

Can anyone tell me what that means and what can I do to fix this? Thanks.

Have you installed anything on your device prior to receiving this error?

I installed slacker radio and a game. I deleted both of them already and Im still getting the error message.

Can anybody help me?

Problem solved. I wiped my phone under the options menu then I restored my back up file and everything is fine now.