I downloaded the screen shots and found that it is a known issue on specific system environments.

PDF Driver is a virtual printer. Therefore the installer needs to call "OpenPrinterW" (a Windows API) in order to add local port. The error message (zeon1.gif) means that "The specified print monitor does not have the required functions".

We confirm that this problem can be reproduced on few specific environments only, most of our users can normally install PDF Driver on their machines.

We will try to find a solution as soon as possible.
Sorry for the inconvenience.