I've decided that I want to play the last 4 hours I have in my account from the beta, but I have vista now, and vendetta won't start. Something with vendetta.rlb... I'd like to spend my last hours :(

You cannot update a client that old to production. Re-download VO from here http://www.vendetta-online.com/x/download?platform=win32&x=50&y=28 uninstall the one you have, and install this.