ipnat - local redirection

Greetings,

I'd like to do a local redirection, to redirect from TCP port 4888 to 4889
(This is for Oracle Management Agent 10g).

Here's what I've tried:
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# cat /etc/ipnat.rules
rdr dmfe0 161.117.169.92/32 port 4888 -> 127.0.0.1 port 4889

# ipnat -CF -f /etc/ipnat.rules
0 entries flushed from NAT table
0 entries flushed from NAT list
localhost as destination not supported
4: syntax error in "rdr"
/etc/ipnat.rules: parse error (-1), quitting
--------------------------------

I also tried using the non-lo interface address, even though the how-to says
the packets must be redirect to a different interface than the one they come
in on (ref. http://www.unixcircle.com/ipf/ipf-howto.html).
--------------------------------
# cat /etc/ipnat.rules
rdr dmfe0 161.117.169.92/32 port 4888 -> 161.117.169.92/32 port 4889

# ipnat -CF -f /etc/ipnat.rules
0 entries flushed from NAT table
0 entries flushed from NAT list
5: can't resolve hostname: 161.117.169.92/32
5: syntax error in "rdr"
/etc/ipnat.rules: parse error (-1), quitting
--------------------------------

Any ideas?

Regards,

Dave Seddon