From the icon on the left and the screenshots below, it appears that Rapidshare has developed their very own download/upload manager for premium users. It's been floating around forums for a few days now. The quote below is supposed to be an official comment from them.
We have developed our own program that is now in its late beta testing. The
program allows premium users to download and upload files with a new size of
4000 MB per file.
Please note that the language can be changed in the programs options in
English or German.
At the moment we have no documentation to this program, please ask our support
if you have any questions.
The highlight of this comment is the increase of the maximum file size to 4GB. Wonder if that's because they use FAT32. However, Since the validity of this program hasn't been verified, I'm not providing links to it. Besides, it's fairly easy to find it online.