Contact InterActual Support and they will walk you through it. support.interactual.com. There is a phone number in there somewhere and that’s probably the easiest way to get to the bottom of it.
BTW – the most compatible are PowerDVD, WinDVD (beyond 4) and CinePlayer. If you strip down to just one of those and then reinstall eDVD (may not be necessary to do that) I bet it will work.
Conflicting programs can include Nero decoder, Divx, certain DVD ripping software