are you using a free account? Have you put it inside premium_accounts.conf?

the premium_accounts.conf contains the following entries:

For each hoster that offers premium accounts, you can set your

account details here. Feel free to try any supported hoster.

It's up to the plugin if it is able to work with the data.

rapidshare.com_user =
rapidshare.com_password =
uploaded.to_user =
uploaded.to_password =
megaupload.com_user =
megaupload.com_password =

In any case doesn't work also the simple http download, the following link doesn't work:

http://www779.megaupload.com/files/3df3f8af96c4ba380edfdb1ee85db29b/BEN%2010%20-%20ULTIMATE%20ALIEN%20-%202x35%20-%20L%27epurazione%20-%20by%20Alex69Picci.avi

Just to add another information, the rapishare links does works well. I think that the problem is related to megaupload.
This is the log of download using FlashGet:

Fri Jan 06 14:06:47 2012 Connecting www779.megaupload.com:80
Fri Jan 06 14:06:47 2012 Connecting www779.megaupload.com [IP=209.222.128.219:80]
Fri Jan 06 14:06:47 2012 Connected.
Fri Jan 06 14:06:47 2012 GET /files/3df3f8af96c4ba380edfdb1ee85db29b/BEN%2010%20-%20ULTIMATE%20ALIEN%20-%202x35%20-%20L%27epurazione%20-%20by%20Alex69Picci.avi HTTP/1.1
Fri Jan 06 14:06:47 2012 Host: www779.megaupload.com
Fri Jan 06 14:06:47 2012 Accept: /
Fri Jan 06 14:06:47 2012 Referer: http://www779.megaupload.com/files/3df3f8af96c4ba380edfdb1ee85db29b
Fri Jan 06 14:06:47 2012 Cookie: __utma=216392970.140084148.1314518260.1325840875.1325854382.58; __utmz=216392970.1314518260.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); l=en; user=BD70WNWUEOZFGA50FAC7Y8J8L0BTJGMB; __utmb=216392970.1.10.1325854382
Fri Jan 06 14:06:47 2012 User-Agent: Mozilla/4.0 (compatible; MSIE 5.00; Windows 98)
Fri Jan 06 14:06:47 2012 Pragma: no-cache
Fri Jan 06 14:06:47 2012 Cache-Control: no-cache
Fri Jan 06 14:06:47 2012 Connection: close
Fri Jan 06 14:06:49 2012 HTTP/1.1 200 OK
Fri Jan 06 14:06:49 2012 Server: Apache/1.3.37 (Debian GNU/Linux) PHP/4.4.7
Fri Jan 06 14:06:49 2012 Content-Type: application/octet-stream
Fri Jan 06 14:06:49 2012 ETag: "TWM86HHC"
Fri Jan 06 14:06:49 2012 Content-Length: 262156288
Fri Jan 06 14:06:49 2012 Content-Disposition: attachment
Fri Jan 06 14:06:49 2012 Cache-Control: private
Fri Jan 06 14:06:49 2012 Content-Transfer-Encoding: binary
Fri Jan 06 14:06:49 2012 Accept-Ranges: bytes
Fri Jan 06 14:06:49 2012 Start Receiving Data!

OK will take a quick look at it!

fixed it!! Do you know the way megaupload handles limits? I'm not sure these are integrated properly

Figured it out myself! Should be alright now!

So now I have to build the new version ? why FlashGet is able to download the simple http while DD isn't able ?

OK, I have built the version 1279 and now works both the MU plugin and the simple http.

Thanks !