Connecting to database fails

   I'm trying to install and run an abandoned PHP-based application (xrms
found on sourceforge.net last updated a decade ago) on Slackware-14.1
running httpd-2.4.16, php-5.6.24, adodb-5.14, and postgresql-9.3.4.

   When I try to load the install.php script in firefox-45.3 I see this
error:

Syntax error in file:
/opt/xrms/include/adodb/drivers/adodb-postgresql.inc.php
ADONewConnection: Unable to load database driver

   That driver name is a softlink to adodb-postgres7.inc.php because the
calling script looks for that specific name and I've not found where this
driver is called.

   With no other PHP applications installed here I have no experience in
determining where this stoppage occurs. Pointers on how to isolate the
source of the problem, than how to fix it, are needed.

TIA,

Rich