IMPORTANT:
Star Force ProActive has recently implemented a deactivation option for DCS: MiG-21bis. In order to avoid an unneeded activation of previously activated module due to Start Force protection changes, please:
Deactivate the module
Exit DCS
Start DCS again
Activate the module after starting a MiG-21BIS mission
NOTE for Windows 8 users: It is possible that you will receive a warning notifying you that module can't write to registry after it activates. Confirm this notification and let the mission start. You won't get into the cockpit this time. Exit the mission and restart DCS. Load another MiG-21BIS mission: you should be in the cockpit this time.