You probably just have to clear the queue (don't know how to spell that) in your installer. When you try to install something and it says main script execution failure that means that app wont work with your firmware most likely and installer automatically puts that app in your queue so when you try to download something else it is really trying to download the app that wouldnt work originally. So basically you just have to click on anything to install and it there should be a button saying clear queue and click that and you will be set.