I just upgraded computers and have been trying for a week to install the Pro X . I even purchased the upgrade and received the CD in the mail. See attached picture what it's showing.
In addition to what @CubeAce (Ray) has written, I'm a little confused by your statement that you received the CD in the mail because your screenshot clearly shows that the installer is attempting to download the necessary files for VPX from the Magix servers. Is it the case that the CD actually contains only the Magix Download Manager?
The 1603 error and the error message indicate you do not have the correct security permissions or something is blocking the installation eg the antivirus program you have installed.
The account you log on to the computer with must be an Administrators account.
If you are using Windows Defender it is probable that the Protected folders feature is blocking the install - try turning this off by:
Open Windows Start menu.
Type Windows Security and open it
Select Virus & threat protection in the left action bar.
Scroll down to Ransomware protection on the right pane.