WAS is a Windows Audio Session driver and was introduced with BIAB 2018. Since you have BIAB 2017, it won't be there.
For what it's worth...
I'm not sure that a re-install will solve the problem seeing that all other files play correctly. It seems more likely that these couple of non-playing files are corrupt in some way.
As a last-ditch attempt... go to the link below and set the Audio and MIDI as shown by the numbers on the images. This set-up is the most basic and sturdy when it comes to problem solving.
Before changing the settings, though, under the "Options" menu there is a choice to save preferences. I suggest you do this just in case you need to re-load the original settings that you had.
http://www.pgmusic.com/forums/ubbthreads.php?ubb=showflat&Number=461558#Post461558Lastly, if you have any musical USB devices plugged in, unplug these and re-connect. USB connections sometimes cause issues and need to be reset.
Regards,
Noel
P.S. I just noticed that you had a bar-based letter on you lead sheet (bar 69). I wondered if this might be the stumbling block. In the below SGU file, I've removed that letter. Does this 4th version of the file work?
https://www.dropbox.com/s/f2nn1wrlrgaifd0/ovation99%20-%20Tunica%20Motel%204.SGU?dl=1