I have made a simple game that I want to convert into a runnable jar so I can show others and launch it without Eclipse.

In Eclipse I:

1. Right clicked on Project
2. Export
3. Java > Exectuable Jar File
4. Launch Configuration: CTB (1) - Click The Block

It made a jar with a MANIFEST.MF containing:

Manifest-Version: 1.0  
Class-Path: .  
Main-Class: uk.co.robertmerriman.ctb.main.CTB  

This was all extracted to my desktop in Click-The-Block.jar

When I double click, nothing happens.
When I type "java -jar Click-The-Block.jar" into CMD, I get the following error:

Error: Unable to access jarfile Click-The-Block.jar.