Gaming Minicraft Help

[Sora de Eclaune]

I've downloaded these versions of Minicraft:

• Minicraft (Downloaded here.)
• Minicraft Plus (Downloaded here.)
• Minicraft Delux [sic] (Downloaded here.)
• Infinitytale (Downloaded here.)

However, Minicraft and Minicraft Plus do not load. They give an error upon attempting to execute the jar files that you're supposed to use to execute them.

The errors are:

• "Failed to load Main-Class manifest attribute from K:\Minecraft\Minicraft\Minicraft\ld22.jar"
• "Failed to load Main-Class manifest attribute from K:\Minecraft\Minicraft\Minicraft Plus\ld22.jar"

As Minicraft Delux and Infinitytale work just fine and also load from jar files, it's not anything to do with the version of Java.

How do I fix this?

Edit) They also do the same thing on my laptop, so it's not the computer's fault, either.