Well, I don't know anywhere near enough to realistically comment on this, but I'll zip an email to a theoretical physicist friend of mine and get his comments.
Long distance space travel would be real cool and I'll volunteer to be the first to go, one way or round trip.
I know a Ph.D. theoretical physicist at a reasonable university and I've known him for 35 years. I'd trust his judgement. Here's what he has to say when I asked him what he thought of the paper:
"Not much. We have been accelerating particles to near (0.99999+) light speed for many years and have not noticed any "anti-gravity" effects.
A quick ArXiv search for any papers by Dr. Franklin Felber reveals ...
none. But he does have a Ph.D."
Looks like a publicity hound.