Lol, this has been cracked for around half a year. Plus, the jar file won't be picked up as a virus because it probably has a trojan downloader in it. There is a line of code in it that downloads and runs the trojan downloaded from a server.
Here is me trying to run it on my virtual machine
http://tinypic.com/player.php?v=2cndqua&s=6
Reasons for me to believe it is unsafe :
1. Doesn't work
2. Cracked file is larger than uncracked? Since when are cracks larger? I believe you remove checks, not add extra shit?