Formatted input from text file

[IK]

I'm attempting Project Euler's problem 11.
http://projecteuler.net/problem=11

Currently, my code looks like posted below, and it gives
    object.Error: Access Violation
at runtime.

Question: how to read that grid from a text file? (See link above.)
If you have ideas for using something other than uint[20][20], please say.
Thank you.

import std.stdio;
import std.stream;

void main()
{
        uint[20][20] grid;
        BufferedFile input_file;

        input_file.open("p011_input.txt");
        input_file.readf("%(%(%d %)\n%)", grid);
}