asterisk users - Sep 2007 - Zaptel ztdummy module causes playback to fail

I'm using asterisk 1.4.11 and Zaptel version 1.4.5.1 with kernel
2.6.22. I have the ztdummy module loaded, which is using zaptel and rtc.
When the ztdummy module is loaded, sounds are not heard when using the
asterisk "background" command. When the ztdummy module is unloaded,
which also removes zaptel and rtc, sounds are heard.

I've also tested this under kernel 2.6.21 with the same results.

The zttest program reports an error when ztdummy and associated modules
are not present, and hangs when they are loaded.

This is an AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ with 2GB ram.

Any idea of what is causing this problem and how it can be solved?

Chris
-- 
Chris Nestrud
Email: ccn at panix.com
http://www.panix.com/~ccn/