Class 'COM' not found

From PHP 5.4.5, COM and DOTNET is no longer built into the php core.you have to add COM support in php.ini:

[COM_DOT_NET]
extension=php_com_dotnet.dll

Otherwise you will see this in your error log: Fatal error: Class 'COM' not found

The extension is included with php 5.4.5 for Windows.

See COM Requirements:

COM functions are only available for the Windows version of PHP.

.Net support requires PHP 5 and the .Net runtime.