Chuckie: I believe I got step one and two, but the third (with the contact sheet) you lost me on, sorry. Do you think you could explain a little more detailed? Buying the PDF2ID is sadly not an option.
Adamjury: Usually when I need help like described in my first post, the PDF files are corrupt in such a way that when I use the script MultiPageImporter it will first of all crash/stop the script. It also usually means that I can not view the page in Acrobat because it simply won't show or I get a message that this is not how it should be (can't remember at the moment exactly what Acrobat tells me). Luckily I can still open the page in Photoshop manually.
Thanks a lot for your help so far, both of you!
Another question on the side by the way, is there some webpage where you can learn Acrobat tips & tricks? Of course I know there are, but not all are good. I.e. I have helped my boss a lot after learning how to save optimized PDF-files about a month ago in the easiest situations that is enough to get the file printing again.