Sum of Diagonals of a 5 x 5 double array

hi guys,

this is my code but after compiling it, this statement appears "1>c:\users\patricia\documents\visual studio 2010\projects\double_array\double_array\double_array.cpp(58): error C2109: subscript requires array or pointer type
"
what does that array or pointer type means?

this is my code

#include <iostream>
#include <iomanip>
using namespace std;

const int Dimension = 5;

int main()
{
  int list[Dimension][Dimension];
  int value = 1;
  for (int i = 0; i < Dimension; ++i)
    for (int j = 0; j < Dimension; ++j) 
	{
      list[i][j] = value++;
      cout << setw(2) << list[i][j] <<
        (!((j + 1) % Dimension) ? '\n' : ' ');
    }

  value = 0;
  for (int i = 0, n = 1; i < Dimension; ++i, ++n)
    for (int j = 0; j < Dimension; ++j, ++n)
      if (!(n % Dimension) && (!(Dimension % 2) ||
        n / Dimension != Dimension / 2 + 1))
        value += list[i][j];
  for (int i = Dimension - 1, n = 0; i >= 0; --i, ++n)
    for (int j = Dimension - 1; j >= 0; --j, ++n)
      if (!(n % Dimension))
        value += list[i][j];
  cout << "\nSum is: " << value << endl;
  return 0;
}

please help me!

thank you

by the way this is what my teacher wants: