Switching from hardcoded username and password to database

I decided that I wanted to switch from using the hardcoded username and password and use the "username and password from database" feature. I created a table using phprunner,

username varchar 50

password varchar 50

index int 50 PK
And went into my project and selected use the "username and password from database" and picked username and password fields from the drop down. I did not set any advanced features, just accepted all defaults. ..seemed simple enough... built output and copied files to web server...
i then used Navicat software to log in and add a username and password for myself..
I get an error no matter what username and password i type in...
It does not look like phprunner is generating the correct SQL statement to check the username and password (see below). I am not an expert at this, so I am not sure what is causing the problem.
Thanks in advance!
--Charlie
PHP error happened
Technical information

Error type 256

Error description Unknown column '' in 'where clause'

URL **/pmdb/login.php?

Error file /srv/www/html/pmdb/include/dbconnection.php

Error line 26

SQL query select * from `_UserSecurity` where ``='myusername' and ``='mypassword'