help with PDF - undefined function

I am trying to get his sample code from the php manual to work: I get the following error: Fatal error: Call to undefined function: pdf_open() in /home/sites/site5/web/pdf.php on line 3 pdf_open() is a built-in function of PHP, so I'm not sure why this isn't working. I'm using pdflib 3.03 and PHP 4.0.3pl1 on linux. Any ideas? I can see that it is indeed making the file in the directory, but why is this function 'undefined'? Jon From the manual: Most of the functions are fairly easy to use. The most difficult part is probably to create a very simple pdf document at all. The following example should help to get started. It creates the file test.pdf with one page. The page contains the text "Times Roman outlined" in an outlined, 30pt font. The text is also underlined. <?php $fp = fopen("test.pdf", "w"); $pdf = pdf_open($fp); pdf_set_info($pdf, "Author", "Uwe Steinmann"); pdf_set_info($pdf, "Title", "Test for PHP wrapper of PDFlib 2.0"); pdf_set_info($pdf, "Creator", "See Author"); pdf_set_info($pdf, "Subject", "Testing"); pdf_begin_page($pdf, 595, 842); pdf_add_outline($pdf, "Page 1"); pdf_set_font($pdf, "Times-Roman", 30, "host"); pdf_set_value($pdf, "textrendering", 1); pdf_show_xy($pdf, "Times Roman outlined", 50, 750); pdf_moveto($pdf, 50, 740); pdf_lineto($pdf, 330, 740); pdf_stroke($pdf); pdf_end_page($pdf); pdf_close($pdf); fclose($fp); echo "<A HREF=getpdf.php>finished</A>"; ?>