Hi there,

you are right it is missing. With the last update the effect files have been moved to the resources of the engine, but the PhysicsActor class still tries to load the file from the regular content folder.
This problem is fixed in the new version which I hope to get online in a few days. Until then you can download the effect here and copy it into the "Content" folder.

Thanks for reporting this.

Greez
Duallity