Hi, here is the problem...

I have a printer connected on USB to a WinXP PC...I've set the printer as shared with no restriction on my windows PC and I've also disabled any firewall. Then I've tried to connect and print from my Ubuntu Laptop (I have Ubuntu 8.10 installed).

I go to system > adiministration > printer to install the new printer. I've choosen Windows printer via SAMBA, type in the printer address in field (something like xxx.xxx.xxx.xxx/HPLaser) and the complete the procedure and installed the correct driver.
Now the strange thing occur...
The first time I've tried to print the printer manager on Ubuntu ask me for authentication, so I used the adiministrator log-in parameters set in the WinXP PC and all seems to be ok: my doc has been printed perfectly!
But then, when I tried to print another document nothing happen and the printer status monitor on Ubuntu report this error: Tree connect failed (NT_STATUS_ACCESS_DENIED)...

I've tried to remove and re-install the printer on Ubuntu several times and every time this problem occur: first print job ask for authentication and then work fine, after this I get the error wrote above and no authentication prompt is shown...

Is there anything I can do to solve this?

Thanks a lot!