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.