When a driver for GP-Pro EX is added or updated, you need to install it in both GP-Pro EX and Pro-Server EX.

Pro-Server EX is different from Pro-Server Ver. 4.x, and it does not share the driver file with GP-Pro EX.
Pro-Server EX has the driver file in the folder, in which it has been installed, and the install path is also archived in the registry as the folder.