samba - Apr 2010 - add Samba Printer to Win Server 2008 64bit problem

Hey,

i'm currently stuck into installing a samba printer onto our WinServer
2008 64bit.

first some facts:
Samba:
-Ubuntu 9.10
-samba 3.3.2 downgrade (normally 3.4 is installed->64bit access problem)
-printing backend: cups

i installed the printer on the samba server. I can add the printer in
XP 32bit and Win 7 64bit using a KonicaMinolta PS driver as client
driver.
But i can't install any driver (tried so downloaded and Windows
standard) on any of our W2008 servers. They're all 64bit.
When i choose "connect" on the printer in Explorer
(\\faxserv1\printers ->in german \\faxserv1\Drucker) it states that no
driver is installed on the samba server. I choose yes to install a
driver choose an postscript driver and it starts copying the files.
after a moment an error message appears: "printerdriver-setuperror.
access denied"

First investigation was access problems, but because it works in Win7
64bit i have no good idea to find a solution anymore...

Looking forward to hear your ideas, and thanks in advance.