I can only assume that the standalone is a 64-bit application. Basically some computers are 32-bit, others (well, most newer ones) are 64-bit. 32-bit computers can run 32-bit applications (and below, like 16-bit etc), but not 64-bit, whereas 64-bit computers can run all those _and_ 64-bit applications. If you want it I can go into more detail about what 32/64-bit actually means, however I don't think it would help you much... I'm surprised though if the standalone is a 32-bit, as I would have thought a standalone should be 32-bit so it can run on more computers. I'm sure someone can give a better answer than me (preferably someone on the actual Greenfoot team)

Thanks - that makes sense, or at least the explanation does, but as you say, I woul;d have thought the standalone would have been 32-bit, too. Are all the "non-standalone" versions 64-bit, too? This might cause problems if they are... Thanks again, Ian

I just tried it on my 32-bit XP machine, and it worked fine. It could be a corrupt download/incomplete ZIP extraction, but that seems unlikely. How exactly are you attempt to run Greenfoot? Are you auto-running the stick, using the "Run Greenfoot" shortcut on the stick root, or running Greenfoot in the greenfoot directory on the stick? Post here which one you're using, and maybe try one of the others in that list to see if they work.