When I try to add some Megaupload links , Jd always show "unknow size".
And when JD connect the Megaupload link , log shows my ip has been blocked by Megaupload and have to wait 25min .
I have tried reconnect some times but log also shows that my ip has been blocked.
Finally, I use cryptload to download the Megaupload links , it works well and I just wait 25sec before download next link.
So maybe it is the bug of JD ?
sorry for my english.....

Allow java.exe and javaw.exe in your firewall and virus software. Also disable html/web scanner in your virus software.

If this doesn't help, please provide a detailed log.

Look here for logging instructions.