samba - May 2005 - Authentication of Windows share fails

Dear all,

I am trying to access a windows share on one WinXP computer from my SUSE 9.2 
box using either smb:// kio-slave on konqueror or the smb4k application. 
Neither seems to be working anymore, as the authentication fails and keeps 
asking me for the password, while at least via konqueror it was no problem 
last week. I tried several accounts and also tried changing passwords.
?
I can, however, access a share with user and password on another windows 
machine. Also the questionable machine is reachable from other WinXPs just 
fine.

Any pointers where to look?

Cheers,
Kostas