Try restarting your iPad. Press and hold the Sleep/Wake button until the red slider appears. Slide your finger across the slider to turn off iPad. To turn iPad back on, press and hold the Sleep/Wake until the Apple logo appears.
Yep, I had the same problem - cancelling sync within the Video app, and the same with the iPod app (in fact the playlists and purchases werent showing either)
Synced the iPad to itunes, and they all appeared
I'm not sure if this is a bug or a feature, but the Apple Remote app cant see my old Apple TV, which used to work perfectly on the iPad