Hello, EmpireMinecraft, and I like to ask all of you who are reading this thread, that, why can't I install any snapshots or prereleases? Whenever I open the jar of the snapshot / prerelease, it says: Java Exception. What does that even mean? Someone please help me and explain why.
Because you installed it wrong Are you opening it? You have to click show in folder, go to your .minecraft folder, then go to your bin folder, click copy on your .jar, paste it onto the desktop, then go to your downloads folder that you opened before, click copy on your 1.3.jar, and paste that into your bin folder.