changing Oscommerce to use ? instead of / as url parameters

I have an Oscommerce site hosted by godaddy that recently developed an error: No input file specified.
I have tried various options to no help..
I need to change the way the url is passed from http://www.mtlafrica.com/index.php/cPath/46 to http://www.mtlafrica.com/index.php?cPath=46

Below is my code:

#

function tep_show_category($counter) {
  global $tree, $categories_string, $cPath_array;

  for ($i=0; $i<$tree[$counter]['level']; $i++) {
    $categories_string .= "&nbsp;&nbsp;";
  }

  $categories_string .= '<div class="link_prod"><a href="';

  if ($tree[$counter]['parent'] == 0) {
    $cPath_new = 'cPath=' . $counter;
  } else {
    $cPath_new = 'cPath=' . $tree[$counter]['path'];
  }

  $categories_string .= tep_href_link(FILENAME_DEFAULT, $cPath_new) . '">'; //this is the default that is being used to call links as http://www.mtlafrica.com/index.php/cPath/46 

  if (isset($cPath_array) && in_array($counter, $cPath_array)) {
    $categories_string .= '<span style="color:#C40000" >';
  }


  $categories_string .= $tree[$counter]['name'];

  if (isset($cPath_array) && in_array($counter, $cPath_array)) {
    $categories_string .= '</span>';
  }

  if (tep_has_category_subcategories($counter)) {
    $categories_string .= '-&gt;';
  }

  $categories_string .= '</a>';


  $categories_string .= '</div><br />';

  if ($tree[$counter]['next_id'] != false) {
    $this->tep_show_category($tree[$counter]['next_id']);
  }
}

#

Please assist.