Couple of things you can try to reset the iPad:
1) First thing you can try turning the iPad on and off: Hold down both the home and power button until you see the "Slide to Lock" button appear. Slide to lock and after a bit, the iPad will go dark (no spinning circles to be seen). Then, press and hold the power button until you see the white Apple logo appear.
2) Or, you can do a reset/reboot of the iPad: Do the above, but don't select "Slide to Lock." Keep holding the two buttons until the screen goes black and then the white Apple logo appears.
Note that it make take some time until (a) the white Apple appears or (2) the iPad homescreen comes back. Have patience ... it'll happen.
Then, after doing one or both, try opening Documents2Go. If it didn't help, let us know and we'll try something else...
Marilyn