asterisk users - May 2006 - Got reject for frame 0, but we only have others!

Hi all,

what could be the cause for the following messages? 

May 22 12:44:53 WARNING[3791]: chan_zap.c:8498 zt_pri_error: 2 !! Got reject for
frame 0, but we only have others!
May 22 12:44:54 WARNING[3791]: chan_zap.c:8498 zt_pri_error: 2 !! Got reject for
frame 0, but we only have others!
May 22 12:44:55 WARNING[3791]: chan_zap.c:8498 zt_pri_error: 2 !! Got reject for
frame 0, but we only have others!
May 22 12:44:56 WARNING[3791]: chan_zap.c:8498 zt_pri_error: 2 !! Got reject for
frame 0, but we only have others!
May 22 12:44:57 WARNING[3791]: chan_zap.c:8498 zt_pri_error: 2 !! Got reject for
frame 0, but we only have others!

They flood my asterisk log since some days and i can't relate the date
they started to a specific configuration change. I haven't yet noticed
any bad side-effects, but i tend to feel better without any WARNINGs
in my * log. 

I have already enabled "bri intense debug span 2", but i have to admit
that i am not able to recognize any valuable pattern not to mention any
sense at all :( (maybe that's because i am a systems administrator and
not a telco guy). 

At least there is some kind of BRI traffic each time such a message is
logged. The BRI debug can be found at 

    http://skayser.de/mls/au/reject-bri-intense-debug.txt

Maybe some of you are more capable to interpret those cryptic BRI
messages.

asterisk*CLI> show version
Asterisk 1.2.7.1-BRIstuffed-0.3.0-PRE-1p

Cheers

- Sebastian