URGENT! Finishing and eliminating bugs from Android NFC attendance register.

Hello, i need to get an application working perfectly in less than 48 hours, I managed to get the project started from someone who claimed he had already done something similar, But he wasn't able to finish it for some reason. anyway now i have an unfinished application with major bugs, and my bachelor defense is in 2 days. Basically, this application is supposed to record student attendance in a classroom using NFC(Near Field Communication). So far, we've managed to develop the app to a level, but when i run it, and hit any button, the application crashes, so i was wondering if you can finish it, and how soon can you do it? i have attached a copy of what we've developed so far, so you can take a look. Thanks