Thanks for your reply Dro!
Yeah it's a bit weird because after installing Wacup for the first time I had the problem of Wacup not opening immediately after double clicking a file - or just clicking on the Wacup shortcut. It took about 20-30 seconds for the window to show up but after that it was fine. Googled the problem and tried reinstalling Wacup - I even used both x86 and x64 versions. Still, after a restart, the window would only open very late on the first run. After that it was fine.
Then I decided to uninstall both and reinstalled Wacup like I mentioned earlier and voilĂ , the Wacup window popped up instantly. Very weird indeed.