Warning Message: possible use of uninitialized variable 'ordticket'

I have never had that warning for an array.

Maybe it is because you are not using a dynamic array which means that the ArrayResize() will not work.

    int orderstotal = OrdersTotal();
    int orders = 0;
    int ordticket[][2];
    ArrayResize(ordticket,orderstotal);
    double lots = 0;
    for (int i = 0; i < orderstotal; i++)
    {
        bool BuyVar=OrderSelect(i, SELECT_BY_POS, MODE_TRADES);
        if (OrderType() != OP_BUY || OrderSymbol() != Symbol() || OrderMagicNumber() != 9)
        {
            continue;
        }
        ordticket[orders][0] = (int)OrderOpenTime();
        ordticket[orders][1] = OrderTicket();
        orders++;
    }
    ArrayResize(ordticket,orders);

would possibly not give you the warning 

EDIT: changed a typo after reading the following post 

    int orderstotal = OrdersTotal();
    int orders = 0;
    int ordticket[30][2];                         //NOTHING CHANGED
    ArrayResize(ordticket,orderstotal);          //INSERTED
    double lots = 0;
    for (int i = 0; i < orderstotal; i++)
    {
        bool BuyVar=OrderSelect(i, SELECT_BY_POS, MODE_TRADES);
        if (OrderType() != OP_BUY || OrderSymbol() != Symbol() || OrderMagicNumber() != 9)
        {
            continue;
        }
        ordticket[orders][0] = (int)OrderOpenTime();
        ordticket[orders][1] = OrderTicket();
        orders++;
    }
    ArrayResize(ordticket,orders);               //INSERTED

No Warnings. But as you said i have not changed int ordticket[0][2]; instead of ordticket[30][2];

Sorry, my typing finger must have slipped

int ordticket[][2];

 of course the [] should be empty

Well, learn something new every day

    int ordticket[30][2];                  
    Print(ArrayRange(ordticket,0));
    ArrayResize(ordticket,5);         
    Print(ArrayRange(ordticket,0));
    ArrayResize(ordticket,40);         
    Print(ArrayRange(ordticket,0)); 

 I thought that static arrays could not be resized, but after your post I tried this bit of code and it seems that they can.

In the documentation for ArrayResize()

int ordticket[30][2]={0};

Or dynamic array as point by GumRai.

Good catch, you should report this bug to Metaquotes. (With mql5 you get a warning and the array is not resized).