ipnat syntax error?

[Juergen Heberling]

Could someone please check me on this ...

fw1# ipnat -CFn -f /etc/ipnat.rules
0 entries flushed from NAT table
1 entries flushed from NAT list
syntax error error at "-", line 1

/etc/ipnat.rules contains:
map  em0 192.168.1.0/24 -> 204.134.75.1-10
.. snip ..

line 1 in the rules file is the example from the FreeBSD handbook.
I'm running FreeBSD6.0 stable.

TIA
Juergen