The three RealTracks used (RT# 1717, 1718, 1719) are from Set 156. I suggest:

Check in the RealTracks Preferences that your RealTracks folder location is what you expect (empty if just using the internal hard drive Band-in-a-Box folder.

Check in the RealTracks Picker, show n/a checkbox and sort by Set # column. See if there's a range of sets that are N/A - maybe you just need to install some missing sets.

Are all RealTracks missing, or just a few, and do they show up as N/A [RT Folder] or N/A [ST2 Missing], or just N/A?
PG Music Inc.