Runtime Error While Initializing Global Variables

My code simply reads problems from 42 different text files and solves them, and then prints out the solution.

I know it is not a good practice but I am using global variables such as

Customer *customers;
vector<int> *schedules;
double **distanceMatrix;

and suppose that I have to do this.

My problem appears while initializing distanceMatrix:

distanceMatrix = new double*[n];
for (int i = 0; i<n; i++)
    distanceMatrix[i] = new double[n];

The part that I could not understand is, I get a runtime error not in the first problem, not in the second, but at random problems between 9 and 25. Hence, I am pretty sure that files are well-formatted.

I do not have any syntax errors.

Sometimes, I get runtime error while reading from text file 9, sometimes 13, sometimes 22 etc.

I think there is some trick I am missing while initializing global variables. Maybe I need something like flush.

What am I doing wrong?

I have also tried reading only one file at a time, not reading all the files with a loop. i.e. not initializing the global variables again and again. I had no runtime errors.

A minimal example:

vector<int> **trucks;
vector<int> **presellers;
Customer *customers;
Customer *sortedCustomers;
double **distances;
int type, m, n, t, D, Q;
int id;
void readFromFile(const char *prefix, int instanceId)
{
    stringstream fileName;
    id = instanceId;
    fileName << prefix << instanceId << ".txt";
    FILE *file = fopen(fileName.str().c_str(), "r");
    fscanf(file, "%d %d %d %dn", &type, &m, &n, &t);
    fscanf(file, "%d %dn", &D, &Q);

    trucks = new vector<int> *[m];
    presellers = new vector<int> *[m];
    for (int i = 0; i<m; i++)
    {
        trucks[i] = new vector<int>[t];
        presellers[i] = new vector<int>[t];
    }
    customers = new Customer[n];
    sortedCustomers = new Customer[n];

    distances = new double*[n];
    for (int i = 0; i<n; i++)
        distances[i] = new double[n];

    int i, d, q, f, a;
    float x, y;
    fscanf(file, "%d %f %f %d %d %d %dn", &i, &x, &y, &d, &q, &f, &a);
    createCustomer(i, x, y, d, q, f, a, t); // read depot
    for (int j = 1; j<n + 1; j++) // read customers
    {
        fscanf(file, "%d %f %f %d %d %d %dn", &i, &x, &y, &d, &q, &f, &a);
        createCustomer(i, x, y, d, q, f, a, t);
        for (int k = 0; k<a; k++)
            fscanf(file, "%d ", &(customers[j].list[k]));
    }




    for (int j = 0; j<n-1; j++) // compute distance matrix
        for (int k = j + 1; k<n; k++)
            computeDistance(j, k);


}

int main()
{
    const char *inputPrefix = "t"; // prefix of the instance files.

    int begin = 1;
    int end = 42;

    for (int i = begin; i <= end; i++)
    {       
        readFromFile(inputPrefix, i); // read instance from file
    }
    system("pause");
    return 0;
}

Inputs:

https://www.dropbox.com/s/kdchj1g3e13aic8/files.zip?dl=0