Hello Robo, 

   This error usually occurs during the installation of the printer port which is part of the virtual printer installation. It is installed through a Windows Service called the "Print Spooler" service. That service can occasionally "lockout" access to add or remove printers, port monitors and ports if it thinks that it is "busy". This may occur (for example) if you a printed a document prior to the installation, particularly if the application used for printing is still open.

   Your best bet for success is to ensure that all applications are closed before installation. If the error re-occurs, then restarting the "Print Spooler" service is usually effective. If you do not know how to restart a Windows Service, then the easiest way to achieve that goal is to shutdown and restart the computer. Once the computer has re-started, attempt to install PDF reDirect at that point: it should work then.

   This error has occured to me once, and to another user as well. In both instances, rebooting before installation fixed the problem.

   Best regards,

Michel