Unity 5 importing scenes

Hello people, I am having lots of problems since I downloaded unity 5, projects that worked perfect with unity 4.6 give random errors with unity 5. I was wondering if anyone else had this problem or knows how to solve it.

Code stopped working, code that worked perfectly fine in unity 4 like this script: top.size = new Vector2 (MCam.ScreenToWorldPoint (new Vector3 (Screen.width * 2f, 0f, 0f)).x, 1f); top.offset = new Vector2 (0f, MCam.ScreenToWorldPoint (new Vector3 (0f, Screen.height, 0f)).y + 0.5f);

gives the error "Assets/scripts/setup.js(35,15): BCE0019: 'offset' is not a member of 'UnityEngine.BoxCollider2D'."

Also I get errors with every script:

I am not a unity/programming pro just someone starting out with unity, does anyone know a solution for these problem's or should I just go back to unity 4.6?