Check out thread below for info/tips. Vulcan's toward the end worked for me.
Sorry for the copy/paste here, one more post and I can insert live links, thread is on p2 of this board as of now:
forums.crackberry.com/f86/sim-card-rejected-message-104213/
Link helped alot, and went away, after restarting phone, thanks alot man
Search would be great. 4th time I have posted this in SIM Card Rejected threads that were started the past 24 hours.
Your phone is set up for 1XEV while in the U.S. If your phone is in a low signal area and it loses the 1XEV, since the default setting is "GLOBAL", and your SIM card is not activated out of the box, it couldn't get on a GSM network, so therefore you are getting the "SIM Card Rejected" message. The reason the battery pull works sometimes, but comes back is because when you rebooted, your phone found 1X or 1XEV, until the next time it can't find signal (you get the cycle now).
So, simple solution:
1. Manage Connections
2. Select "Mobile Network Options"
3. Network Technology: Change to 1XEV
4. Save