A few days ago the XBMC team released XBMC Eden release candidate 1. In there, the JSON-RPC protocol version has been updated to version 4, which causes problems with XBMC Remote Control for iPad. That’s my bad; I thought the version number would only be increased at the official release, but it seems that I should have accounted for the new version number in the RC cycles already. For everyone that updated to RC1 and having problems connecting, this morning I submitted XBMC Remote Control for iPad 1.4.3 for review by Apple, which fixes the problem. I hope it will be available in the App Store in a few days.
By the way, movie support is going forward, my goal is to release it around the time that XBMC Eden is officially released as well.
Update: 1.4.3 which fixes this problem has been approved by Apple and is available as of March 2.