Authentication scheme fouled up

[B1smooth]

(ibook dual usb 500mhz)

I changed my authentication scheme on ydl 3.0.1 to include ldap via 
authentication gui. I restarted my box and I now have no way of 
accessing my root or user accounts. I tried to get into virtula consoles 
with alt option fkeys and they switch to blank screen consoles but no 
command line. How can I fix this little booger?? What is the conf file 
used to address authentication??

A healthy diet  includes Linux, Linux, and more Linux.