sub getXMLTree{
   my $parser = new XML::DOM::Parser;
   $tree = "";
   if(!open(MYFILE,"$fileName")) {
      $tree = $parser->parse("<root></root>");
      $tree = createHeader($tree);
      $tree = createBody($tree);
   }else{
      close(MYFILE);
      $tree = $parser->parsefile($fileName);
   }
   $tree = updateHeader($tree);
   return ($tree);
}