Which means you are doing the life paths.
So, if you have any amount of neg points, from -1 to -99 in a trait, lets say Compulsion: Arrogance, then you have to put an amount of points into the trait to make it an even number divisible by 100. So lets say it is -65 in Compulsion: Arrogance, well, you need to put 35 skill points to make it an even 100.
Same thing for positive traits. ie, you have +165 in Fast Learner, you must put another 135 skill points in it to take the trait.
DO NOT FORGET, your first -500 points in neg traits will go directly back to your point pool, but thats after you do the trait buy up buy down.