JS Injection
Just one thing to try, as i'm not too sure; If you use Mozilla, when you click on the link to go to the download area, right-click, and select 'open link in new tab'. If, however, it is a javascript pop-up from an existing page, you may want to check the source for the location, and then enter that into the address bar. That should make the URL bar visible, but as i said, i'm not too sure. If you need anymore help, PM me.
Cheers, -Jay.
If you check the source, you might notice something like this:
markupwindow.open("thepagename.php", "toolbar=0, menubar=0, status=0, scrollbars=1, height=600, width=400,resizable=1");
If you want to save the source, it's quite obvious what you should edit ;) but othetrwise just open the page (here: "thepagename.php") in a firefox tab.