How do I import an MP4 video created using the GoPro Hero Camera into the iPad?
From Apple iPad 4 tech spec:


  MPEG‑4 video up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second


So based on that info, FPS and resolution for mp4 are too high. Use Handbrake and convert to H.264 that supports HD on iPad.

Otherwise you can try Azul media player for iPad that can play almost all formats.