Newbie can't get firewall to quit working

["Miller, Jeff - x3328" <JeffM@MOHELA.com>]

Hi all,
For some reason a script I wrote from an ipchains tutorial does nothing.
When I try to get rid of it so I can get back into the machine I cannot. I'm
doing an iptables --flush, then I set all the policies back to ACCEPT.
Everything looks ok;
jeffm@brains:~$ sudo iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
jeffm@brains:~$ 

yet the machine is unreachable (can't even ssh to itself). Rebooting fixes
it. What am I missing?
Thanks,
Jeffm