Style Creator Bot - midi file format ?!?

[Ensemble]

Hi.

I just started using the style creator bot (excellent feature!).

It doesn't accept all midi files though.

Some are easily converted, others can't: the PA4X displays an alert about "midi file not suited for bot processing", or something like that.

Is there a specific midi file format for bot processing?

What are the requirements?

Thanks in advance for any hint.