So I wiped my 8100 using the JL_Commander wipe command using the step-by-step instructions from this page:

How do I wipe the BlackBerry using Jl Cmder? - BlackBerryFAQ

It successfully wiped, and when I try to reinstall the OS (4.2 I think) using Blackberry Desktop Manager I encounter some problems.

I run through all the prompts, and them during the loading process and during the "Reconnecting to JVM" step I get the error message

"Unable to reconnect to the device during a multi-stage load operation."

Now my 8100 is sitting dead on the end of my USB and I don't know what to do.

Any help?

After installing the OS on your PC did you delete the Vendor.xml file?

Ummmmmm, I think I fixed it myself. I found some threads where this was resolved.

What was the resolution?

ravegoo3k what was your solution??
Would be great if you share that information with us and help others.