You could try trashing the com.gvox.Encore.plist in Preferences in your Library folder and also creating a new template. Take any old templates out of the Library > Application Support > GVOX folder and put them somewhere else. You can put them back later if you find they aren't the problem.
Sorry, just guesses here.
Mac G4, OS 9 Encore 4.2.3, OS X 10.4.11, Encore 5.0.5
MacBook Pro 2.4 GHz Core i5, OS X 10.6.6, Encore 4.5.5/5.0.6