[Samba] samba 3.0.1 nmblookup

[samba at tobloml.mailcan.com]

I have FC1 + samba 3.0.1. From Nautilus I can't browse into smb:/// to
view any available domain/workgroup. But I can go directly to any
computer with smb:///conputer-name. 

When I tried to call 'nmblookup -M -- -' I get:
  querying __MSBROWSE__ on 192.168.0.255
  name_query failed to find name __MSBROWSE__ #01

Does anyone know what's wrong? 

PS. Initially I had Samba 3.0.0 and because of the same issue I upgraded
to 3.0.1

thanks,
toblo