asterisk users - Jan 2007 - Avoiding deadlock-line drop problem

Hi,all

Randomly my line drops and when I look in message log file I always see 
the following notice:
NOTICE[14491] chan_zap.c : avoiding deadlock?

The situation appears with no obvious reason, the CLI shows nothing more 
than the zaptel channel hanging up. I have a Asterisk 1.2.10 and Zaptel 
1.2.7 installation on a MSI motherboard with intel chipset 915G.The 
machine is equiped with a TDM40B and a TDM22B.

Can somebody help with this mess?