C# Array index is out of range but index is zero

public int Laenge = 10;
public int Breite = 10;
public Vector3 new_Ver = new Vector3[300];
public Vector3[,] new_Ver_s = new Vector3[11,11];
public Vector2 new_UV = new Vector2[300];
public Vector2[,] new_UV_s = new Vector2[11,11];

void Start () {
int n=0;
for(int l=0;l<=Laenge;l++)
        for(int b=0;b<=Breite;b++)
            if(b>1 || l<Laenge)
                if(b%2 ==1)
					new_Ver[n]=new_Ver_s[l,b]; //this is the line where it says theres a bug.

It says:

IndexOutOfRangeException: Array index is out of range

but debug says all indizes are zero. Is it because the elements are empty? How can i easily put something in there? If i do the same thing with a twodimensional array, there is no problem.
I tried something and replaced new_Uv_s with an empty vector3 variable. It´s still the same error.´

This code runs without errors for me. Any chance you added the initialization after you attached this script to a game object? Check the size of the arrays in the Inspector. Do a reset (gear icon in the upper right of the component in the inspector).