Re: internet explorer cannot download firefox%20setup%203.63.exe from mirror.net cologne.de.
You should search for help in Microsoft's support forum.
Also, I remind you that Firefox 2.0 is outdated and not supported. If you want to use Firefox for daily use, please use Firefox 3.6 (or 3.5), for a faster and more secure experience. You can download it easily at getfirefox.com . There is no need to use mirrors.
If you really want Firefox 2.0, I recommend you browser Mozilla's ftp server at ftp://ftp.mozilla.org or http://ftp.mozilla.org , where all Firefox's builds (and a lot more) are stored. Just make sure you understand Firefox 2.0 IS outdated and no longer supported.