Unfortunately, when I 'wget download.rising-world.net/down…?type=server&filetype=tar', It appears to be downloading a file named 'download.php?type=server&filetype=tar' rather than the actual server .tar file
This seems to be caused by the redirection. Do you still get the right file, i.e. the correct filesize? In this case you could just treat it like a .tar file, or alternatively rename it to a .tar file.
Or you could eventually use wget --content-disposition if it's supported.