send data message with Siemens M20 ERROR 500

Hi all,

When I tried to send 8bit messages from the kannel via M20 modem and set the
conding to 8bit (coding=2)
I got the following error, what is the problem ? and how it can be fixed ?

2002-09-24 11:28:48 [6] DEBUG: AT2[/dev/ttyS1]: -->
001100098150444640F70004A703FF00FF 
2002-09-24 11:28:48 [6] DEBUG: AT2[/dev/ttyS1]: --> ^Z 
2002-09-24 11:28:53 [6] DEBUG: AT2[/dev/ttyS1]: <-- > 
2002-09-24 11:28:53 [6] DEBUG: AT2[/dev/ttyS1]: <-- +CMS ERROR: 500 
2002-09-24 11:28:53 [6] ERROR: AT2[/dev/ttyS1]: CMS ERROR: +CMS ERROR: 500 
2002-09-24 11:28:53 [6] DEBUG: AT2[/dev/ttyS1]: send command status: 1 
2002-09-24 11:28:53 [1] DEBUG: Dumping 0 messages and 0 acks to store