smbumount would nout unmount as user

[Virgo Pärna <virgo.parna@mail.ee>]

    I just upgraded Debian Eth system to Lenny (and also upgraded kernel and changed
from k7 version to amd64 version). Now I'm having a problem. When I mount share from 
Windows XP machine with smbmount, then I cannot unmount it anymore. Both mount.cifs 
and umount.cifs are SUID root. Samba is version 3.2.5-4, kernel 2.6.26-1-amd64.

dragon:~/tmp> ls mnt/blaah.txt
ls: mnt/blaah.txt ei saa kasutada: No such file or directory
dragon:~/tmp> smbmount //gondor/eksport mnt
Password:
dragon:~/tmp> ls mnt/blaah.txt
mnt/blaah.txt
dragon:~/tmp> smbumount mnt
user unmount of mnt failed with 22 Invalid argument
Not permitted to unmount 

from /var/log/messages
Apr 12 09:48:13 dragon kernel: [56071.084009] ioctl32(smbumount:27707): Unknown cmd fd(3) cmd(0000cf02){t:'ￜ';sz:0} arg(00000000) on /home/virgo/tmp/mnt

    Has anyone else had this problem?

-- 
Virgo Pärna 
virgo.parna@mail.ee