That dialog is Dutch for "cannot copy necessary linked files" right?
If so (I don't really read Dutch all that well!), then I'd guess that you should look at your linked files. For instance, if you had edited one of your placed files and left it open in your image editor, that might prevent it from being collected. So, what I'd start with, in your shoes, is I'd save my document with a new name, and hten go to my Links panel and just flat-out delete half of the linked files. Then I'd try to package again. If I could package, then I'd know that one of the linked files I'd deleted was problematic in some way. If I couldn't package, then I'd revert to saved, and try deleting the other half of the placed files. That would allow me to eliminate bad links or corrupt placed files or filesystem problems with linked files as the cause of my inability to package a given document.