I think it says that if you attempt to download something too soon after a previous attempt. If you use JDownloader for Rapidshare it knows how to wait between attempts. It makes using all of the file sharing sites much easier even if you don't have any memberships.
How did Rapidshare cheat you out of your membership?
It's not the wait. They have a countdown clock for that. If they deem the servers are too busy they give you the error message. You can click on it 10 times and the 11th time you get in.
My 6 month membership stopped working after 4 months. The day they changed the site. I was a member for at least 3 or 4 years.