Can't download attachments

Um, hi..

Apologies if it's answered elsewhere, first of all. Since the coming back of the site, whenever I try to download an attachment the dialogue box asks me if I want to download index.php, a file with a size of (-1) bytes. I thought that was normal and bound to get fixed at some point, but now that I logged on another pc  I noticed I can download said attachments(.sol files) with no problem. What could be the problem?

maybe the PC on which you couldnt is the problem. it can be anything