Yeh, I think that's the problem. We upgraded to CS3 and from what I have trawled the internet about it, its a common problem and all the solutions I've found don't work. If I already have the pdf, open adobe reader first and then the doc - then its fine. But as the Marlo story is opened in the browser first it just shuts itself down.
Can you recommend any other pdf readers that I could download and then set as my default? Is Primopdf any good?