I would recommend using AutoHotkey instead of AutoIt. I wrote some bots for fun for a few similar games but skipped Bejeweled in favor of (a simpler) alternative called Diamond Dash. The bot could hold its own but it couldn't beat some of my better friends. To squeeze out the extra performance one has to start doing much more complicated things. For example, the blocks in these games rarely appear in fixed coordinates but slide around, explode (and therefore partially occlude other tiles), etc. Recently, this has been turning into a bit of a cat and mouse game with game developers. For example, they started adding noise on top of sprites to throw off very simple methods.

But there is something very fun in developing scripts that moves your mouse around and play for you. I like that game much better :)