Printers are not being redirected into remote session.
If you open Devices and Printers > Print Server Properties on target RD Session Host and then switch to Drivers tab, you cannot find 2X Universal Printer driver on the list.
You observe the following error when you attempt Installing Universal Printing Module:
When you restart Print Spooler service manually, there is a notification that dependent service will also be restated:
During the upgrade process Universal Printing module is being uninstalled and the warning prevents Print Spooler service from being restarted by 2XInst.exe process.
As a result, installation procedure does not ever start.
Find Dependent service in question and stop it manually.
Install Universal Printing Module per KB: http://kb.parallels.com/en/123690
Start dependent service.