Ron,
1. It looks like it is a 2.6.9 firmware version.
2. Have you tried to go a Command Prompt and type: telnet xxx.xxx.xxx.xxx 5000 (xxx.xxx.xxx.xxx) is your MTCBA-C1-EN2 device IP addresss and try to send the sms from there and see if you are seeing the same problem ?
Note: Make sure you have webbed into your rcell and disable the PPP option -> Disable -> Click on Submit button and do a save and reboot.
3. If you still have a problem, I suggest go our http://www.multitech.com/en_US/SUPPORT/ and create a case for it.
Regards,
BT