If you are still having problems then you can get back to the 1.05 version, without resorting to the CD, by turning OFF the "Show pre-release versions" from the aforementioned "Orb" menu and then you can install the latest full release.
I eventually figured this out after having failed to get he beta after two nights and an entire morning trying - including getting to the "Oh no! I've uninstalled SINs and can't install it again!" stage.
P.S. I found the Orb menu cos' I fiddle with everything when I first get it. But it only just barely lights up when you hover over it, whilst its sibling controls light up far more obviously, and doesn't have a tooltip, when the other graphical object on that level all do - so no, it's not very intuitive and it's inconsistent.
P.P.S. Sorry, but I've been thinking about this a bit more. If you see an icon in any top corner of an application, past experience will mean you will expect one of three things, if anything, to happen when you click on it:
1) An about box for the product will pop up,
2) You will be taken to the companies web site, or
3) If you are already in a web browser - and Impulse has a bit of a Web Browser feel to it - be taken to the home page of the site.