Had to figure this out on my own: Please be aware - as of ZeroXI_uniservice_2_0_0.exe service module - if needing to use the PHP LDAP authentication module while running Apache as a service, the PHP files libeay32.dll and ssleay32.dll must be made available to the Windows system PATH. Recommended way to do this is to modify the system PATH environment variable. More info: http://php.net/manual/en/ldap.installation.php Feature Request - If possible, it'd be nice for future versions of the uniservice module to do this automatically when creating the service.