We're just allow the post to drift quietly into obscurity. 

It's possible.  I've seen this happen before.  Due to the nature of how RapidShare works it is often used to attempt to distribute content of an illegal nature.  The sort that the IWF block.  Possibly you hit an IP that has been blocked?

Hi there,
Bob P posted a diagram of the logic behind the IWF proxy machines in an earlier thread - I'll see if I can find it (as it's from the docs I wrote internally!).
Edit: Here it is:

Basically, what has happened there (from my educated guess) is that the IP of RapidShare has gotten onto the IWF list (remember, all it takes is one verified child abuse image and the IP goes in), so that the connection goes through the proxies.
If there was a problem between you being sent to the proxy and the proxy retrieving the file (here it shows read error, which means the proxy didnt finish retrieving the file) then you end up seeing the error page with why the proxy couldn't honour your request.
Hope this clears up the confusion - I meant to post yesterday but was stuck in a cold server room all day
- Gricey
Edit:  Added image