private function HandleXLSFile($OldFile, $NewFile, $Fields, $SkipLines, $TrimData)
 {
     // Convert the xls file into a CSV file we can easily use
     $XLStoCSVCommand = Config::GetXLS2CSV() . " -x '{$OldFile}' -b WINDOWS-1252 -c '{$NewFile}' -a US-ASCII >/dev/null";
     echo "Executing command {$XLStoCSVCommand}\n";
     system($XLStoCSVCommand, $return);
     if ($return != 0) {
         trigger_error("Error converting xls file to csv file via {$XLStoCSVCommand}", E_USER_ERROR);
     }
     $FileName = $NewFile;
     $newFile = tempnam(Config::getTmpDir(), "{$this->PartyID}-");
     $this->FilesToPurge[$newFile] = NULL;
     $this->HandleCSVFile($FileName, $newFile, $Fields, $SkipLines, $TrimData);
     return $newFile;
 }