Lots of messages on this board about Orbit not integrating/working with Rapidshare in Firefox 2.0.
Here are the instructions, best as I can describe [IMPORTANT NOTE: you MUST have a premium Rapidshare account to use Orbit with Rapidshare]
1) Launch Firefox 2.0
2) Install Flashgot [if you don't already have it]
3) Install Orbit
4) Close all your windows, including browser windows
5) Restart Firefox 2.0
6) Go to Tools > Add On's In Firefox
7) See if Orbit Downloader Firefox Integration 0.40 is shown in the list [if so, great]
8) Now, with your "Add-On's" screen still visible in front of you, click "FlashGot"
9) Click on "Options" for "FlashGot"
10) Under "Download Manager" find "Orbit" if it's not already selected [make sure "Orbit" is in BOLD face]
11) Click "OK" and close your browser
12) Re-launch your browser
13) Go to a web page with a Rapidshare link.
14) Right-click on the Rapidshare link
15) In the menu which pops up, choose "FlashGot Options" > "Orbit"
16) You will see a "Create New Download" dialog box appear from Orbit
17) WAIT for the file size to appear in the BOTTOM LEFT HAND CORNER of the dialog box [may take 5-10 seconds to register]. If the file size which appears has an MB next to it, then you're good. If the file size is KB instead of MB, then you're not getting the download properly.
18) Click OK
19) Your download should begin
20) If you don't follow the instructions this way, Orbit may only download 5KB of the file instead of the full 20MB or 50MB or 100MB [whatever the FULL/REAL file size is]