When the 'render' function occurs, it is indeed creating an audio track.
It is using MIDI, making an audio track of what that MIDI would sound like through the DXi synth.
So you end up with an audio track, but it isn't a 'Realtrack' or Realdrum' track,

The Realtracks/Realdrums are actual studio recordings that are chopped up and arranged to fit your song/style. This is different (although both cause the program to create an audio track) - the render method creates an audio track of how that synth sounds when playing the MIDI, and the RealTracks are composites of actual studio musicians recordings that fit in with your song, (but are not direct 'renderings' of the MIDI info).

The difference is in having a MIDI track highlited and then rendering
or selecting a blank audio track and generating a RealTrack part.

It sounds confusing, but you will get the hang of it.
You need the DXi to render MIDI to audio, but the RealTracks do not require the DXi.
I think what was happening was the program went ahead and generated a realtrack when you didn't have a DXi set up to 'render' the MIDI.

Is that possible?
I am not a BiaB poweruser, but know quite a bit about RealBand and PT, so if others know different, speak up!

I do not work here, but the benefits are still awesome
Make your sound your own!