Nessus and Open Shares

[M.Wagner <wagnermf222 () yahoo com>]

I have Nessus running on a RH Linux 7.3 server and am trying to test for 
open shares on the network (as the security admin).  I have enabled the 
following pluggins but have been unsuccessful in my test on a computer 
with an open share.  The pluggins were:

netbios_name_get.nasl
smb_login.nasl
smb_enum_shares.nasl
smb_accessible_shares.nasl 

I do not login to the Domain and am wondering if this could be the root of 
my problem. 

What am I doing wrong and can Nessus be effective for testing for open 
shares on the network (Win2K mostly)?

M.