This is happening because php is not compiled with dbase support. The method to sort this problem will depend on the following -
webserver
module or cgi
platform
php version
Try checking the php.ini file to see if the following line exists -
extension=php_dbase.dll
//where php_dbase.dll is the name of the extension to load
and if it has a ";" at the start of the line you must delete it and then restart the webserver.
Hope this helps 😉