UC_Order_get_total tries to include date_order causing error

The function includes the following code (starts at line 1455) which was causing some problems on a site that has the Date and Signup modules installed:

foreach (module_list() as $module) {
    $function = $module .'_order';
    // $order must be passed by reference.
    if (function_exists($function) && ($value = $function('total', $order, NULL))) {
      $total += $value;
    }
  }

I had to add && ($function != 'date_order') to the "if" statement to keep '$value' from being an array. A more robust way may be to insure that '$value' is_numeric() before trying to add it to the $total.