Thanks tinypoodle - that gave me the push I needed. I had never run into a problem with the USB connection not being ready in time. When I did the waitusb=20 the problem was solved. It is funny how blind I can be to the obvious, it just never occured to me that the drive wasn't there when needed, after all, it was there at boot time! Sigh...
Anyway, you have done it again. Thanks much for your time and interest and good tips.