If you have a "green" or portable version of KnockOut 2, the process is more direct:
If you face issues, set the installer compatibility mode to "Windows XP (Service Pack 3)" or "Windows 2000." corel knockout 2 win 7 64 bit extra quality
During installation, point the plug-in destination path to your 32-bit host application's plug-in folder. If you have a "green" or portable version