But I found a simple solution for this, I just need to set download port to 800 of the server to get the file downloaded. It is better for you to use Google Chrome in this case since it displays direct url of the file being downloaded from megaupload.
For example, when I try to download from this url:
http://www.megaupload.com/?d=RJKW97IR
(it's for Japanese Drama Ryuusei no Kizuna actually!!)
and your Google Chrome will redirect you to this url after you press "Free Download":
http://www701.megaupload.com/files/d1290ba42f23976e4303318bb31c2f44/Ryusei%20no%20Kizuna%2008%20(704x396).avi
But you are still unable to download, just add ":800" to the url like this:
http://www701.megaupload.com:800/files/d1290ba42f23976e4303318bb31c2f44/Ryusei%20no%20Kizuna%2008%20(704x396).avi
That will solve your problem.
Sometimes by doing this, you can still download although you already get "download limit exceeded" message.