This might be kind of a longshot, but if you hilight the "/Applications/Band-in-a-Box/RealTracks/Data/Style Demos Audio" folder in the Finder and do "Get Info..." on it, what are the permissions set to ?

I have had problems in the past with permissions on the audio folders preventing me from playing the audio.
I will include a screenshot of mine below, and you will note that I have given my account read/write access to the folder.

If you are willing to try, it is easy enough to add your account to the folder with read/write access, then click the gear icon and select "apply to enclosed items".

That has fixed similar problems for me in the past.
Hopefully this helps.

- Jay

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MacPro 5,1/12 core@3.46GHz -- OS X 10.14.6 -- ATI 7970 -- 32 Gig RAM -- Crucial 500GB OS SSD -- Samsung EVO 1TB Audio/Sample SSD -- BIAB 2023 -- Logic Pro X -- Cubase Elements 11 -- Too many plugins