I also have an Icom IC-F121 and the software for that. Its mounted in the mobile and I've programmed that several times the last few years with this same cable. Now it won't work there either. Same issues: it looks like its not communicating. And this is on a laptop-- not even the same machine I'm trying to use for the V8000. I also tried installing the software and cable driver in a Win 7 netbook, with a Win 7 cable driver, and that didn't work, either. Same issues with communicating on the cable.
I also have an Icom F3001 handheld, and a different cable with the 1/8" mini plug to USB connection. And a different software package. THAT works.

Grrrr.... So I know I'm doing everything right.
The maddening thing is, I used the V8000 software last year to program the radio in the first place, so I know it all worked at one point. That's what's so frustrating.
Thanks again. I'll keep working the problem.