Problems with apc extension on wamp server.

Hello!

I am trying to track file upload progress using APC extension.
However, when trying to use, it gives

Fatal error: Call to undefined function apc_fetch() in
C:\wamp\www\old\getprogress.php on line 3

I am using WAMP 2.0, with php 5.2.8
APC extension appear on extensions list and is enabled.

Any ideas what i am doing wrong?

here is the code of getprogress.php:

*
*
$upload = apc_fetch('upload_1');
   if ($upload) {
        if ($upload['done'])
            $percent = 100;
        else if ($upload['total'] == 0)
            $percent = 0;
        else
            $percent = $upload['current'] / $upload['total'] * 100;