I've looked around different forums and could come up with nothing..

This is what happens:

I mount the drive okay, with no problems.
I unmount, again, with no problems, using umount /mnt/win

I try mounting again by:

mount -t smbfs -o user=usr,password=pass // /mnt/win

And I get the error
8380: session setup failed: ERRDOS - ERRnoaccess (Access denied.)
SMB connection failed

Any ideas of what could be causing this?