I tried simply clicking on the download button (as many people on the forums have recommended), and the launcher says it's downloading, yet at the same time I keep getting constant "Connection Error" message. Even when I reloaded the game launcher several times, I still get the same message. I've already registered my copy and setup a Witcher 2 forum account, so I'm at a loss on what to do here.

Being prepared for the flak and stuff, and taking the danger of sounding like a troll, first you should USE THE SEARCH BUTTON. Many have the same problem, most solutions either work or don't, and most wait for the CDPR patch to alleviate this problem.