Thanks for the answer. Unfortunately, it seems the files on the disc are the issue, because while did run the *UPDATER* a few times, and it did download and update lots of files (about 2GB), when running the "add/remove scenery" option, it says it will install 3MB, asks me to insert disc 7 but give the error, and twice, so I think it-s probably two tiles that the files are corrupt.
Is there any way to know which ones they are? (the error popup is too fast on the fist and directly does not show the second), and more importantly download them from somewhere?