I see no indication of any ULX hack in those errors.
I'm not saying ULX can't be hacked, I'm simply saying those errors don't show it.
I searched Google for 'bridgehack lua' and the first response that comes up is "Leak Forums", a big site regarded widely across the Gmod community for not only including leaked pay scripts, but hacks, including exploits from the hackers that release the leaked paid scripts.
Found this for one of the bridge exploit code.
http://pastebin.com/raw/FPHcVQfnI'm currently working from home, so don't have time to look through it deep.