Then you need to double check the setting for the file cache. It needs to be the full path to the ame folder. That error is from a test I run to see if AME can write to the folder - she is saying she can't.
What other features are you after? For the most part vB4 + AME3 gives you about the same feature set as AME2.5x. As far as definitions, I seldom do those and leave it to the community to do (though its generally DJ that ends up doing them all

)