"Encore CS5.1 cannot run in non royalty serialized mode The application needs to be serialized with a royalty bearing serial number " !!what to do
You need to contact adobe support.
In the mean time, you might provide the info Minu requested here:
Do not send any serial numbers, etc here.
If you are on a trial version Encore is not activated.
To make use of Encore you will have to buy Premiere.