Windows – WAMP: Fatal error: Call to undefined function ibase_connect()

I have a Windows 7 Pro x64 that runs the latest version of WAMP v2.4 x64, with Apache : 2.4.4 MySQL : 5.6.12 PHP : 5.4.12 PHPMyAdmin : 4.0.4 SqlBuddy : 1.3.3 XDebug : 2.2.3. When I run my code with the ibase_connect() function, I keep getting this error below:

Fatal error: Call to undefined function ibase_connect()

I've enabled the extension extension=php_interbase.dll in my php.ini without any luck. My PATH variable points to the right php bin folder, and I've tried following the instruction here http://www.alberton.info/firebird_php_windows.html, and also copying the php_interbase.dll file to my C:\Windows\system32 folder, but nothing's worked so far. Am I doing something wrong?

Please help.