In order to find your problem, see what this outputs:
Code:
#include <iostream>
#include <fstream>
#include <string>

using namespace std;

int main(int argc, char *argv[])
{
    ifstream CFG("rungcc.cfg");
    if(!CFG.is_open())
    {
        cout << "Failed to open rungcc.cfg." << endl;
        return EXIT_FAILURE;
    }

    string Configuration;
    CFG >> Configuration;
    cout << "Configuration = (" << Configuration << ")" << endl;
}