No, it turns out it wasn't the cord. The external drive just seems to be unstable. I have given up and installed the complete program on my work laptop, which has lots of room. I made sure everything stayed perfectly still while it installed from the external drive, and it worked.

But now I have to bring my work laptop back and forth from work every day so I can work on BiaB nights and weekends.

I'll try calling again next week. Do external drives simply not work if you are holding a computer in your lap? The external drive was on a table beside me, but it was attached to my laptop by a cord, and the cord moves when the laptop does.