Windows 7 Group Policy Printer not Loading

Question

I'm trying to create a group policy that applies printers to a specific user security group, but facing difficulties.

When loading a GPO with 4 printers in it, all but two PCs load all 4 printers. The two that don't, list the other 3 printers in the same GPO without any issues. The problematic machines are both running Windows 7 and Domain Controller is Windows 2008 R2.

This is what I've tried...

• "point and click" printer install via "add printer" on offending machines. This correctly downloads the drivers an loads the printer.
• Numerous "gpupdate /force /sync" and reboots, the GPResults report doesn't even mention the missing printer. Looking at the Events Viewer I also see no errors.
• Reconfigure printer on print server
• Delete existing driver from "print manager" on print server.
• Re-install printer driver on print server.
• Set driver isolation = shared.
• Tried finding "packaged version" of HP P1606dn driver, but failed
• tried finding driver path, in print management > drivers, but failed
• installed hp universal PCL driver, but failed

GPO is configured as follows

1. user policy > preferences > control panel settings > printers
2. printers are loaded from the printer directory as "shared"
3. Policy "creates" printers every time the user logs in
4. Run in logged-on user's security context (user policy option) is checked for each printer
5. Point and print restrictions are disabled
6. On log-off a VBScript is run to unload all Network Printers
7. Security filtering is on Authenticated Users, within a given OU.

Anybody got any ideas on how to troubleshoot/identify/fix the cause of this problem?

I'm thinking it has something to do with driver install on print server and the fact that the driver i installed is neither packaged, nor does it have an "inf" path. Anyone know how to do this for an HP1606dn printer?

Update: I tried loading the profile on a different PC with no problems. Tried manual install of printer drivers on offending PC and got a permissions error on local admin. Pursuing this further, will keep posted if I have an answer.