Differences between PHP 5.2.x and 5.3.x with respect to the SOAP library

I have developed a PHP site using PHP 5.3.4 and deployed it to a server that has PHP 5.2.6 installed. I am not doing anything fancy; in fact, the only major library I am using is PHP's native SOAP library.

However, when I test my deployed site, I get the error:

Fatal error: Class 'SoapClient' not found in (path) on line 20

Are there any major differences between PHP 5.2.x and 5.3.x with respect to the SOAP library? I have already changed the configuration files. (Well, actually I told the sysadmin to do it, because I don't have permission to do so.) And I get the same error. Any ideas?

EDIT: More information...

1. I'm deployin开发者_StackOverflowg my site to a Windows server.

2. The server has AppServ installed.

3. For some reason I don't understand, PHP's configuration file is C:\Windows\php.ini instead of PHP_DIR\php.ini.

I dont think soap is installed on the server try

sudo aptitude install php-soap

change the following line in php.ini:

;extension=php_soap.dll // before
extension=php_soap.dll // after

this enables the soap extension since PHP 5.0