Run the installer in Compatibility Mode for Windows 7.
The phrase is ambiguous:
While the Just Cause repack may seem appealing to gamers looking to play the game on lower-end hardware or without the hassle of DRM, there are potential risks associated with playing a repackaged game: just cause repack
Disable your real-time antivirus software temporarily to prevent false positives. Run the installer in Compatibility Mode for Windows 7