You get a message like following following an update to PHP:
Unable to load dynamic library '/usr/lib/php4/20020429/gd2.so' - /usr/lib/php4/20020429/gd2.so: cannot open shared object file: No such file or directory in Unknown on line 0
Unable to load dynamic library '/usr/lib/php4/20020429/mysql.so' - /usr/lib/php4/20020429/mysql.so: cannot open shared object file: No such file or directory in Unknown on line 0
The problem is due to the fact that the reference library has changed the directory. solve this, simply edit the php.ini file, find the section extension_dir and to define the new path, for example :
extension_dir = /usr/lib/php4/20050606
Another solution for Linux/Unix is to create a link using the name of the new directory using the command ln -s!