I'm sorry I can't post he .csv file, and it turns out I won't have to!
Your prior suggestion of using TDP 4.2 64-bit version appears to have solved the problem!
I manually installed TDP 4.2 64-bit and the toad.exe is clearly not in 32-bit space, so our internal software repository was incorrect since the 4.0 that I had was definitely 32-bit.
Using TDP 4.2 x64, I imported and saved the template .tim for a newer .csv that just became available (2017-05-23 data) from the source and that was successful.
I then used that same new import template .tim file to import the previos problem .csv (data from 2017-05-22) and it imported correctly.