libsmbclient and smb_opendir: problem with workgroup

[Andreas]

I have a machine in the MYGROUP workgroup that is misbehaving:

[andreas at pandora source]$ smbclient -L duckman -N
session request to DUCKMAN failed (Call timed out: server did not respond after 20000 milliseconds)
(...)

It does exist:
[andreas at pandora source]$ nmblookup duckman
querying duckman on 10.0.7.255
10.0.4.149 duckman<00>

I don't have shell access to see what is wrong, but that is not the point.
The problem is that this missbehaviour is causing network browsing to fail as a whole.

On my client machine I have "workgroup=MYGROUP" and this causes smbc_opendir("smb://")
to return -1. If, however, I use "workgroup=SOMEGARBAGE" (SOMEGARBAGE doesn't exist),
then smbc_opendir() works. Now, as I understand it, the "smb://" url is supposed to
be used to list all workgroups in the network, why should my own workgroup matter?
Or does this "search" need to have some workgroup, even if it is an non-existing one?