You can still extract the files with winrar as if it was a .rar. Try using winrar to open it manually and you should be able to.

It's not even recommended. Unless Java can be turned off while playing, I'd not even play it.

Try the fix that I just posted

For people that can't make the game run:
Step 1: Download java from http://java.com (if you already have java, skip to Step 3)
Step 2: Install it, when it's installed, reboot the PC
Step 3: Make a new text file in the folder where you extracted MHRD
Step 4: Open the file, copy the following text into it:
java -Xmx1G -jar mhrd.jar
Step 5:Click on the File tab, then in the menu that appeared, click Save as...
Step 6:At "Save as type:", click on "Text Documents (.txt)", and in the menu that appears, select "All Files (.*)"
Step 7:for "File name" enter "launch.bat" without quotes
Step 8:Click Save
Step 9:Close notepad
Step 10:Double-click the launch.bat file you just made (It has 2 gears as an icon)
Step 11:If you did everything correctly, the game should launch
-BobGamer455

Run MHDR.exe as an administrator.