[Q] Failed to get Root! topic

I followed instructions to gain root access with Revolutionary S-OFF & Recovery tool 0.4pre4 but received the following error:

Zerging Root... this might take a minute or so.. _rawadb_handle_msg: unexpected CLSE
Failed to get root! :<
Press (almost) any key to exit.

PC firewall & av off, phone's been factory reset, usb debugging and fastboot enabled. No HTC Sync, usb drivers installed.

Am I missing something?

hboot 2.16.0001
radio 2.15.00.05.02
build 4.24.651.1