asterisk users - Jun 2006 - TDM11B FXS port stops working after a reload?

Hi list!

I have a TDM11B (DevKit). When I start asterisk everyting is working fine. 
However as soon as I do a RELOAD from the console the FXS port stops 
working. I have a phone connected to it, when I pick up the phone after 
issuing a RELOAD I get this on the console:

Jun  1 20:27:38 WARNING[14316]: pbx.c:2357 __ast_pbx_run: Channel 
'Zap/1-1' sent into invalid extension 's' in context
'default', but no
invalid handler
     -- Hungup 'Zap/1-1'

And I have no default specified anywhere. When I stop & start Asterisk 
everything is back to normal again :

Asterisk Ready.
     -- Starting simple switch on 'Zap/1-1'


What am I missing here??

This is my /etc/zaptel.conf :
fxoks=1
fxsks=4
loadzone = nl
defaultzone=nl

And this is my /etc/asterisk/zapata.conf :

echocancel=yes
echocancelwhenbridged=yes
echotraining=400

callerid=202
signalling=fxo_ks
group=1
context=intern-all
channel=>1

signalling=fxs_ks
immediate=yes
usecallerid=yes
callerid=asreceived
cidsignalling=dtmf
cidstart=polarity
hidecallerid=no
callwaiting=no
callwaitingcallerid=no
adsi=no
group=2
context=inbound-analog
channel=>4


The problem occurs on diffent asterisk versions, including the latest.

Thanks for any hints / tips!