asterisk users - Nov 2005 - Problem with Zap/1 picking up on OUTBOUND calls from analog extensions

Problem: Zap/1 channel answers when trying to make OUTBOUND call on 
analog phone.

Configuration:
-Asterisk: Running CVS Head from Nov. 1
-X100P card attached to PSTN line; same PSTN line routed to other analog 
phones throughout the house
-Linksys PAP2 ATA with analog phone connected to Asterisk via LAN

See attached zaptel info, zapata.conf and asterisk console log

Details: I can receive and handle inbound calls via the PSTN line 
normally.  My custom IVR, voicemail, call-screening, etc. all works.  I 
can make outbound calls to my ITSP via the analog phone and ATA or 
softphones.

*Sometimes*, when I try to make an outbound call on one of the other 
house phones (one of the phones on the same PSTN line as the X100P), 
asterisk answers the zap channel as if it had an incoming call.  This 
seems to happen about 80% of the time.  Sometimes, pressing just the * 
key will cause the line to be answered.  Other times, it's only after an 
outbound call has been connected (ringing tone heard on the line) that 
the zap channel picks up.

The situation seems to have deteriorated over the last day or two, 
though I haven't changed anything in the zaptel.conf or zapata.conf 
files for several weeks.  The frequency of occurrence seems to have gone 
up signficantly in 48 hours.  My extensions.conf has changed quite a bit 
in that time, but I'm not sure how that should matter.

FWIW, I have the house lines (including the one going to the x100p) all 
connected via a punch-down block that I *believe* is wired correctly, 
though I'm not an expert, so it's possible something's going on in
that
area -- I just don't know what to look for there.  These lines haven't 
changed since before asterisk was installed.  They test properly for 
polarity, and line quality is good.

Has anyone got any suggestions on how to track this problem down?  I'm 
really scratching my head over it!

Thanks in advance.
Cheers,
john

============Output from ztcfg:
$ ztcfg -vv

Zaptel Configuration
=====================

Channel map:

Channel 01: FXS Kewlstart (Default) (Slaves: 01)

1 channels configured.

============zapata.conf:
[trunkgroups]
; define any trunk groups

[channels]

usecallerid=yes
hidecallerid=no
callwaiting=yes
threewaycalling=yes
transfer=yes
echocancel=yes
echotraining=yes
musiconhold=default
faxdetect=incoming
callreturn=yes
immediate=yes
busydetect=yes
callprogress=yes
progzone=us

; define channels
context=incoming
signalling=fxs_ks
channel => 1
=============CLI Output:
     -- Starting simple switch on 'Zap/1-1'
Nov 15 09:24:55 WARNING[816]: chan_zap.c:6088 ss_thread: CallerID 
returned with error on channel 'Zap/1-1'
     -- Executing Macro("Zap/1-1", "incoming") in new stack