How do i fix Network Settings Unavailable on my Samsung Mythic?

It says Network Settings Unavailable whenever i send a text message on my Samsung Mythic, and doesnt send the message. How do i fix this?|||call your network provider and ask them to send your network setting to your phone - oddly it will come as a text message. Normally you need to open it and then delete it - turn phone off and back on - texts messages should now work...