You need the FDF toolkit SDK available from » http://www.adobe.com/devnet/acrobat/fdftoolkit.html. As of PHP 4.3.0 you need at least SDK version 5.0. The FDF toolkit library is available in binary form only, platforms supported by Adobe are Win32, Linux, Solaris and AIX.