I need Help!!

I just bought this MileageManager and I was able to imput data one day, then the next day I tried to open it and a little message box popped up that said 'Java.Lang.NullPointerException' -I cant even access it! How do I get past this?
One more thing is I downloaded a free application called Maufait and it asks for my email address and password; well, I keep giving it and it keeps saying it is registering me, however it is not, I have not been able to use this application at all??? I need help.