Some more bug fixes

• Fixed resource leak causing game to hang when playing a long time
• Fixed potential crash when script code returns an error
• Fixed OK button in loading error screen
• Fixed wrong and/or badly selected display size in fallback screen size selection code
• Removed a SetCurosPos call in hope it fixes the "cursor snaps to screen center" issue some players reported (but also read this for Win8.1. And also this on WoW for a similar issue)