Error message when trying to open java file

[Needsumhelp]

I downloaded this file to try to play a game, and I was told by the person who made the mac version to open the java file. When I try to open the file, I get this message:



Is there any way to fix this?


I have another few more questions:

How do I change the filetype/where the file saves when I take a screen shot?

Where can I get hypercam for mac?

Thanks for the help


EDIT: I forgot to say, I am on version 10.3.9 of Mac OSX