What you have is a version mismatch. ThAT's the kind of message you receive when trying to open a file saved in a newer version than the one you are using.
On window, go the help menu and press the Ctrl key while selecting About InDesign. On Mac it's under the InDesign menu, and you need to hold the Cmd key. This will open a detailed "about" dialog with the full version and build inthe upper left corner. What is it? What version is th training disk labeled for?
Oh man i'm a nut. I don't know why I thought I was running InDesign cs5 but it's actually cs3 - that explains it right? The disc is for cs5. grrrrr. Anything else I can do(except upgrade to cs5?). Thanks.
You'll need to upgrade to CS5.5 at this point.
Damn. Thanks so much for your help & quick replies!