asterisk users - Jun 2006 - bristuff chan_zap.c zt_pri_error line errors?

I'm running bristuff-0.3.0-PRE-1q

The line seems to work but I get these messages on the screen every few 
minutes :

1 received TEI check request for TEI = 81
Jun 20 20:18:05 WARNING[27571]: chan_zap.c:8503 zt_pri_error: 1 TEI remove 
TEI = 127
Jun 20 20:18:05 WARNING[27571]: chan_zap.c:8503 zt_pri_error: 1 TEI remove 
TEI = 127

Any ideas ? Guess this is not normal behaviour?

I'm using a simple HFC-S card

Cheers!