LLTD protocol / uplinked routers / not playing nicely

I have a small network of 3 computers for testing {(1 XP PRO - hardwired on a
Linksys BEFSX41) and (1 Vista build 6000 - hardwired on the same BEFSX41
router) and (1 XP PRO machine on a Linksys WRT54GS - which is uplinked from
the previously mentioned BEFSX41 router)}.

All are under the workgroup name: workgroup

I have loaded the LLTD protocol on the XP machines (KB922120-v5-x86-ENU.exe)
and set up file file and printer sharing for all three machines.

The Vista machine and the XP machine hardwired on the BEFSX41 router share
files and printers just fine (both directions) however, the XP machine on the
uplinked WRT54GS is not able to print or share to the Vista machine (access,
unable to connect).

I can temporarily relieve the problem by double-clicking the "public folder"
icon for the Vista machine that is shown on the XP machine and when it
prompts for "user name" and "password" - enter the "user name" and "password"
for the Vista user presently logged in.

((confused yet))

On the Vista machine - The network map shows all the network devices exactly
where they should be except for the WRT54GS router (it cannot add this
device).

What can I do to get Vista to recognize the uplinked WRT54GS router as a
part of the network map and hopefully thereby get the XP machine on the
uplinked router to be able to print to printers on the Vista machine and
access shared files on Vista machine.