Try doing a battery pull on the device.Once you reinsert the battery and power the device on,dial *228 option 1 to reprogram the device.
Here is a link for more information on the battery pull http://support.vzw.com/clc/devices/knowledge_base.html?id=28061
Sorry I took a little while to get back to you...hazards of working night shift. Anyways, I assume you are trying to get custom ringtones to work on your BB? First, make sure that it is indeed a ringtone that your device can play. Then, make sure the ringtone is placed in the folder for ringtones. It is under Files>File Folders>Media Card>Blackberry>Ringtones. The file can be a mp3 or a .wav file. You can also go to this forum thread at Crackberry's forums for more information at http://forums.crackberry.com/f141/invalid-ring-tone-selected-267719/
Hope this helps,