Windows XP RealBand Build 4 (but it happened with Build 2)

Scenario:
I load an MGx BIAB file or a SEQ RB file.
I highlight an unused channel, set it to channel-type AUDIO (mono or stereo).
I right-click on the channel to invoke the pop-up menu.
I click on "Select and Generate a RealTrack."

The window that next appears is the "Assign RealTrack to Instrument". HOWEVER, even though the "disable RealTracks for this track" box is UNchecked...

(1) the upper left corner of the window is empty. That is, unlike the corresponding BiaB window there is no series of radio buttons labeled "Assign to this Track" with "bass" "piano" and so on.
(2) unlike the corresponding BiaB window, there is no "generate track" button.
(3) If I highlight a realtrack, no "generate track" button magically appears. Ergo, I don't see how to generate a RealTrack.

If, instead, I invoke "Select and Generate RealDrums" that operation works exactly as I expect, which is to say the window and function is just like BiaB.

Huh? Help?

-Mel