Probably just a bad digitizer, you did fully insert the digitizer ribbon cable into the port and clipped the two connectors down right?
The battery does not need to be disconnected for digitizer replacements on iPad 2, 3 and 4 because the LCD does not need to be unplugged during a digitizer replacement, it simply just needs to be moved out of the way.
Note to others, always test the touch screen and home button before fully installing the digitizer as you may just crack the glass when removing it again.