Did you added a icon to it in the app package?
A note: Unix comandline /hello world is actually /hello\ world.
Also the best way to create a app (without Xcode) is to get a existing app from Cydia, SSH it to Putty/Terminal or mount it on your PC/Mac/Linux Desktop, delete the script and modify the other images, create your own script, change app name and put it into your iWhatever.
Did the best to help and welcome to iPad forums and hope you will/have enjoyed your iPad.