Ok - with that information, do you know a few more things?:
1. What color and shape are the "things" you must move into the "circle"?
2. What color and shape are the "barriers"?
3. What color and shape is the "circle" - I only ask this because while this pictorial diagram shows it as a circle, I don't -know- if it is a circle; furthermore, I don't know if is it simple a drawn circle on the grid, or if the grid-lines cross into the circle, or what color the circle edge is, whether that edge is raised in any manner, etc.
Ideally - if you could provide an actual picture of the contest arena (or a link to the contest site?) or something, that might help matters.
Finally - I know virtually nothing about Lego robotics (my extent of knowledge is an old Mindstorms RIS 1.5 system I bought a long while back, and never did much with). Any coding or other advice I could give you would be in the form of ideas or pseudocode that you would need to translate into actual code for the system to try out/play with. I also cannot give you an "out-of-the-box" working solution.
BTW - is this the whole "grid solving robot" thing people are talking about...?
I'm hoping maybe that others who are more knowledgeable about this system can chime in...