These are two alternative download managers:
Free Download Manager:
http://www.freedownloadmanager.org/Orbit Downloader:
http://download.cnet.com/Orbit-Downloader/3000-2071_4-10600926.htmlAlso: who told you you needed to use a download manager?
The site is in Chinese which I am unable to read, but I guess the name of Flashget would be in Latin letters on that page if recommended.
I followed a few links, and the files you seem to want are hosted on FTP. So you might as well try a FTP client on them like Filezilla:
http://filezilla-project.org/download.php?type=client