Solidworks Bridge design simulation errors‏

When I tried to use the simulation to test the strength of my bridge design the error occurred at the the forth step (Mesh and Run) where it said the interferences were detected in the model and would not let me continue on. If you have a solution to my problem please tell me because the assignment is due next week! I have included screen shots of the problems that are continuously interfering with the simulation.

SolidworksSimulation