I'm having what appears to be a similar problem, judging from the screenshot. I'm away from my main computer at the moment, but I have this problem on my laptop (Dell 1535 studio, Vista 32, ATI Mobility 3450HD Radeon, about three years old) and on a desktop (Dell, Vista32, ATI card [sorry can't see name at the moment], about three years old).
I can start construct and it seems to work, but like in the screenshot I cannot see tiles/sprites etc when I drag them onto the layout editor. They appear fine in the resource tab and in the picture editor. I can also see them when I run the program in a browser.
I am in the process of updating the video card drivers as suggested above, (but its taking a while because I'm having some problems with that, possibly because I can only use the drivers from the Dell website). I'll report on my progress after the drivers have been updated.
At any rate, I think it is worth noting that even if it is not Scirra's fault, this issue could be a fairly common occurance and one that would put off new users. I am persisting because I know how good this program is after using construct 1 and having used mmf and other game editors in the past. To be honest though, if I hadn't used construct 1 I would be unlikely to persist given that all the other game editors I've tried run fine on both these computers, especially since I don't see any warning on the site like "note this program uses the latest technology and requires graphics drivers to be updated or you may encounter such and such problems".