Fred,
This is indeed unusual behaviour.
If you decide to try a reinstall, keep in mind that you don't need to reinstall all the Realtracks and Realdrums. Only the BIAB/RB file.... that's the one that contains the programs' software.
Do you run BIAB/RB in administrator mode? If might be that if the programs are writing temp files, they need to have administrator privileges.
You can set the admin privileges by right-clicking on the program's shortcut and then selecting "Properties". Admin privileges is under the "Compatibility" tab.
Also, when you installed BIAB 2016, what option did you use?
Lastly, have you changed anything to do with your computer recently?
Regards,
Noel