Kinda depends on both the facts and state law, to tell you the truth, and I don't know the real story on either one. I don't know of any state where uninsured operation means you are automatically at fault in an accident though, which is what it would take to win on the law part. She'd also have a shot on the fact part if her drunkenness was not the sole cause of the accident in a purely causative way, for instance if the truck was stopped with no lights on at night around a blind corner on the ramp, or something like that, so that a sober person could have hit it just as readily. She could still have gotten the manslaughter conviction for her drunkenness being a major contributing cause, without it being the sole cause.
My personal opinion is that she ought to have her probation revoked for even filing this piece of shit, though.