
I don't believe there will be any problems at all with this experiment. In fact, congratulations to the scientist who first raised the story that the world could end as a result of this experiment, because he has actually given the LHC a huge amount of publicity.
The main goal of this experiment is to find the Higg's Boson, a particle that confers mass to every other particle which also has mass. It is only predicted by theory thus far, but I'm not confident that this exxperiment will prove the theory at all. In fact, I think that it will only raise more questions than answers.
Kevin