Troubleshooting printshares/CUPS in Zentyal 3.2

[robb]

I have a Zentyal 3.2 x64 server with file and domain services active. I also installed and activated printersharing. In CUPS I added a networkprinter that is accessable from a HP Jetdirect card on a local IP address with port 9100
I activated the networkcard for CUPS to listen on the network where the printer is.

Now I am hitting some permission problems.

I have an old XP Professional laptop that I added to the domain. When I log in to the domain with that laptop, the shares are mapped correctly.
I added the printer by connecting to \\zentyal\sharedprinter
When I look in printers and faxes on the WinXP laptop, I see: access denied for the network printer.

The user is member of the printusers group and in Zentyal ACL I added printusers to be able to print.

Another problem I face is mapping LTP1 to that network printer. When I give a: net use lpt1: \\zentyal\printer I get a 'systemerror 66'
This is a well know error, a lot of similar problems are found with a googlesearch, but none of them seem to solve my problem.

Can anyone give some hints to troubleshoot?