Fatal error: Call to undefined function ldap_connect()

Hi,
I have a bit of a problem... I had a Windows 2003 server up and running fine for some time now, but went away on holidays and someone reinstalled the WAMP set up using XAMPPs in order to get mod perl working on the server and broke the Drupal install... I poked around a bit trying to repair it, but decided I didn't want to share the server with the other applications so set up a LAMP server and moved the site. I can log in with the original user password, but I am unable to get LDAP Integration to work, I get the following error each time I attempt to log in:

Fatal error: Call to undefined function ldap_connect() in /var/www/drupal/sites/all/modules/ldap_integration/ldap_integration/LDAPInterface.php on line 107

PHP5-LDAP is installed

Any ideas what I am missing on the LAMP configuration?