Nestor87-
I recently got a refurb XV6800 and had the same issues. I tried to run both Olipro 2.40 and NueSPL 2.47 and it would freeze without completing the unlocking process. I eventually went to the Restore to Stock tutorial here:
http://forum.ppcgeeks.com/showthread.php?t=21161
Initially that wouldn't work either. Then I extracted the files and flashed the .nbh file for the old rom using the SD card. That worked and got me to a point that I had an unlocked ROM and a non-GPS radio that I was then able to update.
Good luck!
WorkerB