Plese help!

We’ve got REAL problems running Asterisk 1.2.7.1 on Fedora Core 5 with Cisco 7936…
Then i try to enter any confrence (we use ztdummy) from Cisco Conference Station 7936 the Asterisk server is crashing !!!
We have no problems with other software or hardware IP Phones…
PLESE HELP !!! I can post any information regarding this situation…

Asterisk 1.2.7.1
CHAN_SCCP 20060408
Fedora Core 5
Cisco CS 7936

Here is the backtrace from CORE file:
(gdb) bt
#0 0x006da4ad in strcasecmp () from /lib/libc.so.6
#1 0x004774a1 in conf_run (chan=0x988a200, conf=0x981d9f0, confflags=0) at app_meetme.c:969
#2 0x0047a785 in conf_exec (chan=0x988a200, data=0xecdfa8) at app_meetme.c:2002
#3 0x0808e4cf in pbx_extension_helper (c=0x988a200, con=Variable “con” is not available.
) at pbx.c:553
#4 0x08090228 in __ast_pbx_run (c=0x988a200) at pbx.c:2227
#5 0x08090e07 in ast_pbx_run (c=0x988a200) at pbx.c:2553
#6 0x00222c6f in sccp_pbx_startchannel (data=0x988a200) at /usr/include/asterisk/strings.h:155
#7 0x008a33b6 in start_thread () from /lib/libpthread.so.0
#8 0x0073733e in clone () from /lib/libc.so.6

(gdb) bt full
#0 0x006da4ad in strcasecmp () from /lib/libc.so.6
No symbol table info available.
#1 0x004774a1 in conf_run (chan=0x988a200, conf=0x981d9f0, confflags=0) at app_meetme.c:969
usr = Variable “usr” is not available.

enable debugging, reproduce the problem, and post the debug log