Php XSLT processor

[Captain coffee]

Hi guys

You guessed i'm up agaisnt the wall so any assiatnce is gratefully recieved. I'm using PHP with an apache server running under windows XP. the version is 5.1.1.

What I want to do is to transfom an xml file with an XSLt file. I can do this through the browser so I can be fairly confidant thatboth XSL and XML are 'wellformed' . To try and achive this with PHP I have used  XSLTProcessor and because I go the following error message

Class 'XSLTProcessor' not found

I tried a new approach using xslt_create and got a similar message in fact

Call to undefined function xslt_create()

I have checked out the the PHP info page and it does tell me I have libXML support with versio 2.6.1

So I do not understand why it cannot find the classes. Any help would be warmly welcome

Thanks in advance

CC