error in extracting pdu

Hi,

I use a modem ericcson F221m, I have no problem to send SMS but i can
not succeed to receive ones.
I have this error :
2003-09-22 15:41:40 [5] DEBUG: AT2[Telecel]: <-- +CMT: 31
2003-09-22 15:41:41 [5] DEBUG: AT2[Telecel]: <--
069142318000F904099142318002F900003090225153900006CDE4740A9201
2003-09-22 15:41:41 [5] ERROR: AT2[Telecel]: got +CMT but pdu_extract
failed

The configuration of my SMSC is like this :
group = smsc
smsc = at2
smsc-id = "Telecel"
allowed-prefix = "30;31;32;33;34;80;81;08;09"
modemtype = ericsson_f221m
device = /dev/ttyS0
alt-dcs = true
speed = 9600

And my modem like this :
#MODEM

group = modems
id = ericsson_f221m
name = "Ericsson f221m"
detect-string = "F221m"
init-string = "AT+CNMI=3,3"
#no-smsc=true

Thanks for any help.

Jérémie from Libreville