"iptables: Invalid argument" with kernel 2.4.20

[cees-bart <ceesb@xxxxxxxxx>]

hi all,

by reading the iptables tutorial (version 1.1.11) i've constructed
a configuration that forwards a port on MYMACHINE to OTHERMACHINE:

# Generated by iptables-save v1.2.6a on Tue Nov 12 17:41:18 2002
*nat
:PREROUTING ACCEPT [221:38784]
:POSTROUTING ACCEPT [78:7025]
:OUTPUT ACCEPT [72:6769]

-A PREROUTING -d MYMACHINE -p udp -m udp --dport 27960 -j DNAT \ 
                           --to-destination OTHERMACHINE:30000 

-A POSTROUTING -d OTHERMACHINE -p udp -m udp --dport 30000 -j SNAT \ 
                           --to-source MYMACHINE 

-A OUTPUT -d MYMACHINE -p udp -m udp --dport 27960 -j DNAT \
                           --to-destination OTHERMACHINE:30000 

COMMIT
# Completed on Tue Nov 12 17:41:18 2002

this setup works fine on kernel 2.4.19 with iptables 1.2.6a.

BUT, the last rule (OUTPUT) fails with message "iptables: Invalid 
argument" when running under 2.4.20.

i tried iptables 1.2.7a as well, but the result is the same.

am i doing something wrong?

thnx,
cees-bart.