asterisk users - Feb 2012 - Hangupcause on DAHDI 2.4.9-svn-r9328 channels - Asterisk 1.4.36

Hello,

I face a problem on some dahdi incoming calls. Hardware is Xorcom with 
Elastix 1.6.2.27/Asterisk 1.4.36/DAHDI 2.4.9-svn-r9328 inside. Setup is 
3 incoming BRI (euroisdn), ringing phones are 3xSNOM320, 4xSNOM300 and 
4xFXS phones.

On this calls, phones are ringing and when picked up, nobody on the 
other end. Other phones are still ringing and same behavior when trying 
to pickup. No need to say that *8 doesn't work better.

I checked one of those call and found that the callee hanged up before 
someone picked up the call.

What I have in logs (debug)

logger.c:     -- Channel 0/1, span 3 got hangup, cause 111
rtp.c: Channel 'DAHDI/7-1' has no RTP, not doing anything

further

app_dial.c: Exiting with DIALSTATUS=CANCEL

further

logger.c: > Protocol Discriminator: Q.931 (8)  len=8
logger.c: > TEI=82 Call Ref: len= 1 (reference 1/0x1) (Sent to originator)
logger.c: > Message Type: RELEASE COMPLETE (90)
logger.c: > [08 02 81 d1]
logger.c: > Cause (len= 4) [ Ext: 1  Coding: CCITT (ITU) standard (0)  
Spare: 0  Location: Private network serving the local user (1)
logger.c: >                  Ext: 1  Cause: Invalid call reference value 
(81), class = Invalid message (e.g. parameter out of range) (5) ]

Questions are: why are phones continuing to ring after the call had been 
canceled? What are hangup cause 111 and Invalid message/parameter out of 
range.

Thanks for any hint

-- 
Daniel