[Samba] Win 2000 mount the share twice

[idm]

I have notice that Win 2000 client (SP4) are mounting
the samba share more than once.
There is no problem with XP Pro or Win9x.

p            username mygroup   1822   Win2000client   (10.1.1.1) Tue Feb 15 16:03:53 2005
p            username mygroup   1822   Win2000client   (10.1.1.1) Tue Feb 15 16:03:44 2005

Is there a way to change this behavior (modify register)?
(when i use preexec, it runs twice two)

Thansk in advance for your help.