Have you read through the forum posts. Chances are your question has been answered already.
I would recommend performing a master reset on the device. It will clear out any corrupt data:
http://support.garmin.com/support/searchSupport/simpleCase.htm?caseId={593366a0-7ae0-11e2-65d0-000000000000}&kbName=garmin
If you continue to have problems, follow the troubleshooting steps in the following article:
http://support.garmin.com/support/searchSupport/simpleCase.htm?caseId={8a5f1480-ddf1-11e2-7dd9-000000000000}&kbName=garmin
Albert