I didn't see anything about audio interface/sound card either.
What are you using? Has it been connected and working for long?
I do not use BIAB or RealBand connect to anything. Both are used on my laptop for some production and creation purposes only (arrangements, realtracks etc).
No needed to have an interface connected to RB or BIAB cause the studio interface is AVID/ProTools for recording.
For all mixing (in the box) I transfer the files to Harrison MixBus 3.