samba - Jun 2004 - VMWare; WinXP guest can browse every machine except host Debian, and vice versa

The setup:

My VMWare host is Debian 2.4.24, and runs Samba 3.0.2a-Debian,
on fixed IP address 10.0.0.9. Other computers can see and use
services on this server. Samba is browse master and domain master
browser for the workgroup. An external host runs dnscache and
a tinydns for the local domain.

VMWare is 3.2.0 build-2230, configured with bridged networking
only (though I previously tried both NAT and host-only).

My guest is now WindowsXP (I tried 98 also, same problem as
I'll describe). It's in the same workgroup, and has a fixed
IP address 10.0.0.11. I'm logged in as administrator, as I
haven't created any additional accounts yet. I enabled WINS
to the host (in desparation, I don't know what it does).
Guest can ping host, and vice versa, and both can do DNS
lookups with or without the local domain suffix (same as
workgroup name).

The problem:

Both host and guest can see all other computers on the LAN and
use their services, but neither can see or connect to the other.

I've run Ethereal on XP and tcpdump on Debian, and packets from
nmb lookups and browse requests are visible from both ends, but
I always get "host not found" errors. I can show the dumps if it
helps. I'm not seeing errors in the nmb or smb logs.

What could possibly be wrong?
What more can I do to diagnose it?