I can add myself to the list of people with 1.22 freezing problems now.
Maybe it's a good idea for everyone having this problem to list what they
got enabled and what they got disabled, so maybe we can find a common factor
and exclude some services/configurations.

The box is running at a customer who is not close by, so I cannot try a
double m0n0 setup to debug nor capture the packets in this case.
In my case it's one running on a 3 port wrap board with a 128 Mb CF, I'm
using identical wrap hardware (even rev. nr of boards match) at other
customers without problems.

Enabled : 

Minimal set of Fw rules
Traffic shaper with 
Captive portal with internal userlist (no radius)
Dns forwarder
Nat
Dhcpd

Disabled/not using : 

Dynamic dns
vlans
pptp
ipsec
dhcp relay
wireless
proxy arp
snmp
external syslogging
static routes

Did I miss something critical ?

Keep up the good work.

Regards, 
Jurgen van Vliet