samba - Mar 2011 - cant use Samba windows printer drivers on WindowsXP32

hi everybody,

after some trouble i an know able to upload and set printerdrivers via 
cupsaddsmb and windows apw.

but there are two errors.

- i cant use the driver on a windows xp 32, if does not get installed as 
root previously.

- i have a Oki Execution series 7411 and used the PS Driver.
when printing to that printer i get in smb.log
Unable to print file to es7411 - client-error-not-authorized

in cups error.log i get
[21/Mar/2011:10:43:19 +0100] Returning IPP client-error-not-authorized 
for Print-Job (ipp://localhost/printers/es7411) from localhost

but i can print (if connected as root) to other printers on the same 
machine?

where could be the error?

best regards
thomas