App error 523 means that a system process has died, and the only way to fix it is to wipe the OS and reinstall it.
Since you are within 14 days of purchase you can go exchange it, or you can fix the DIY way.
To do it, you need to get javaloader. IF you search the forum you will find it. One member here has a link in their sig for an app call jl_commander which is a convenient UI for javaloader. You will also need to latest version of the OS for the flip.
I don't have exact instructions in front of me for javaloader or jl_commander, but here is the jist of what you need to do.
1)BACKUP YOUR BLACKBERRY!!! You are going to obliterate every bit of data on there. Also backup your memory cards contents if you have device encryption enabled.
2)Use javaloader or JL_Commander to wipe your black berry. Instructions for this are on this forum somewhere.
3)Install the new OS following the instructions in the sticky at the top of this forum (or click this link for it
). Be sure you do delete the vendor.xml file.
4)Restore your data from the backup.
5)Rejoice that you only spent an hour fixing your BB instead of wasting gas to go back to the store, or to the service center.