You must use Safari Mobile in order to add a shortcut in your home screen.
It's very easy to customize your iPhone or iPad application icons with iCustom !
See the features page to learn more about all you can do using iCustom shortcuts.
If you have validation errors during your shortcut configuration, this means that I think that you didn't configure your app shortcut correctly.
I STRONGLY advise you to correct the errors before continue to the next step.
If the shortcut you add on your home screen doesn't launch your app :
You MUST use Safari mobile browser to use iCustom and have the ability to add a shortcut on your home screen.
iCustom adds the generated shortcut to your homescreen using the iOS configuration profiles mechanisms. You must accept its installation to get your shortcut on your homescreen.
This is safe as these profiles only contains informations about how to add a "webclip" (a shortcut) on your homescreen
Simply long tap the icon and tap the little cross on its top-right corner, like for any other iOS app on your homescreen.
To completely and safely remove the shortcut from your device, remove its configuration profile from the Settings app > General > profiles