samba - Apr 2008 - Samba seems to be working - but Linux client can't see windows machines

I'm not sure whether this is a samba problem or not - but thought 
someone on the list will probably know.
After quite a bit of fiddling - I think Samba is now doing what I want 
it to - providing file and printer sharing for my windows machines.
However - my Centos 5.1 Linux box Can't browse the windows machines from 
the gnome/nautilus interface. I know the windows machines are publishing 
their shares - because I can write to files on the windows machines 
(from the linux box) if I address them by IP number and share name. When 
I try to browse the windows network in Nautilus I can see the workgroup 
which both the linux box and windows machines belong to (this is not a 
domain). If I try to double click the workgroup I get the error:

The folder contents could not be displaced. Sorry couldn't display all 
the contents of "Windows Network: aardvarkwg"

I have also seen the following error in my logwatch:

--------------------- samba Begin ------------------------ 

 
 **Unmatched Entries**
 nmbd/nmbd_incomingrequests.c:process_name_release_request(118) 
process_name_release_request: Attempt to release name AARDVARKWG<1d> from
IP 192.168.0.2 on subnet 192.168.0.201 being rejected as it is one of our names.
: 1 Time(s)
 
 ---------------------- samba End ------------------------- 

Could this be relates? 192.168.0.2 is a windows box. 192.168.0.201 is 
the Centos Linux box.

Thanks

Richard