Networking through a router

I am having an unbelievably bad time trying to get my WinXP machine to
see my Redhat 7.3 Linux box in any way. I set up Samba 2.2 by
explicitly following the instructions at
http://www.linuxorbit.com/howto/sambahowto.php3 and it still doesn't
work. I'm thinking that my router is the problem. It's a Netgear
RP614v2. I have it hooked up to my cable modem and my Win and Linux
pcs each plugged into a port on the router.
When I double click on the workgroup from windows, all I get is the
error "'Workgroup' is not accessable. You might not have permission to
this network resource. Contact the administrator of this server to
find out if you have access permissions." "The list of servers for
this workgroup is not currently available."
I did set up the same username and password on both computers, and am
logged in as that user on the windows box when I attempt the
connection.
Thanks.

BTW, I checked the Samba logs on the Linux box and none of them show
anything more than the start of services - no attempts to connect are
shown.