Unable to get the spreadsheet_excel_writer class running

Hi All, I am using PHP version 4.0.3pl1 which works fine with Apache as the web server. I am getting the following error whenever I am running a test program, Parse error: parse error, expecting T_STRING' or T_VARIABLE' or `'$'' in Spreadsheet/Excel/Writer/Workbook.php on line 161 Fatal error: Class spreadsheet_excel_writer: Cannot inherit from undefined class spreadsheet_excel_writer_workbook in Spreadsheet/Excel/Writer.php on line 45 Workbook.php has the following code in line 161, $this->_parser =& new Spreadsheet_Excel_Writer_Parser($this->_byte_order); Any pointers to the solution? Thanks Abhijeet.