Ubuntu doesn't provides any package for php5 dbase support. So to install and configure php 5 dbase support you need to download the appropriate php source code from the php.net website at http://www.php.net/downloads.php for the latest one and for the old versions you can download from http://www.php.net/releases/

The procedure to configure and install php5 dbase package is mentioned here.

Install the following package. if you already have then omit this step

$ apt-get install php5-dev

Download the php source code and extract the source code in some directory.

Navigate to the downloaded php source code directory by following the below mentioned step

$ cd PHP-SOURCE-CODE_DIR/ext/dbase

After that execute
$ phpize

Then
$ ./configure

Followed by a,
$ make

Then
$ cp modules/* /usr/lib/php5/20060613+lfs/

Edit the php.ini
$ vim /etc/php5/apache2/php.ini

In the extention section add,

$ extension=dbase.so

Restart Apache

$ /etc/init.d/apache2 restart

That's it. You have php5-dbase installed.