Sounds like a network or an account issue. You can try removing and reinserting the battery and trying again.
Otherwise if that doesn't fix it, you will need to contact technical support for troubleshooting. You must call from a different phone and have your phone with you. 800-922-0204 or *611 from another VZW mobile phone.
I get this error message when I attempt to send PIXs/VIDs to Non-VZW Customers who do not have Enhanced Messaging. Not sure this is the problem, but thought I might offer it as a possibility.