Unistim transfer crashes asterisk

Hi

we are running asterisk 1.6.2.11 rpm install on centos 5.5
There is a PRI (wildcard) using dahdi and phones using unistim

whenever a unistim phone initates a transfer, this causes asterisk to crash!!
Any ideas anyone?

[2010-08-23 09:21:06] NOTICE[27161] chan_unistim.c: Asked to get a channel of format alaw while capability is 12 result : alaw (8)
[2010-08-23 09:21:06] VERBOSE[27161] chan_unistim.c: – unistim_request(652@Kevinc)
[2010-08-23 09:21:06] VERBOSE[27161] app_dial.c: – Called 652@Kevinc
[2010-08-23 09:21:06] WARNING[27161] translate.c: no samples for alawtolin
[2010-08-23 09:21:06] VERBOSE[27161] app_dial.c: – USTM/652@Kevinc-0 is ringing
[2010-08-23 09:21:06] WARNING[27161] translate.c: no samples for alawtolin
[2010-08-23 09:21:06] VERBOSE[27162] app_mixmonitor.c: == Begin MixMonitor Recording USTM/635@Marguerite-1
[2010-08-23 09:21:07] VERBOSE[27161] app_dial.c: – USTM/652@Kevinc-0 answered USTM/635@Marguerite-1
[2010-08-23 09:21:08] VERBOSE[27139] res_musiconhold.c: – Stopped music on hold on USTM/635@Marguerite-1
[2010-08-23 09:21:08] VERBOSE[27139] pbx.c: – Executing [h@macro-dial-one:1] Macro(“USTM/635@Marguerite-1”, “hangupcall,”) in $
[2010-08-23 09:21:08] VERBOSE[27139] pbx.c: – Executing [s@macro-hangupcall:1] GotoIf(“USTM/635@Marguerite-1”, “1?skiprg”) in $
[2010-08-23 09:21:08] VERBOSE[27139] pbx.c: – Goto (macro-hangupcall,s,4)
[2010-08-23 09:21:08] VERBOSE[27139] pbx.c: – Executing [s@macro-hangupcall:4] GotoIf(“USTM/635@Marguerite-1”, “1?skipblkvm”) $
[2010-08-23 09:21:08] VERBOSE[27139] pbx.c: – Goto (macro-hangupcall,s,7)
[2010-08-23 09:21:08] VERBOSE[27139] pbx.c: – Executing [s@macro-hangupcall:7] GotoIf(“USTM/635@Marguerite-1”, “1?theend”) in $
[2010-08-23 09:21:08] VERBOSE[27139] pbx.c: – Goto (macro-hangupcall,s,9)
[2010-08-23 09:21:08] VERBOSE[27139] pbx.c: – Executing [s@macro-hangupcall:9] Hangup(“USTM/635@Marguerite-1”, “”) in new stack
[2010-08-23 09:21:08] VERBOSE[27139] app_macro.c: == Spawn extension (macro-hangupcall, s, 9) exited non-zero on 'USTM/635@Marguerite-1<Z$
[2010-08-23 09:21:13] VERBOSE[27180] logger.c: Asterisk Event Logger Started /var/log/asterisk/event_log