I had the same problem with logging in to the printer to either set the network settings or changed the password.
I found the answer on the driver cd. I installed the user guide, this automattically installed a network user guide also. You can view this from the okidata catagory from the progam menu. In order to log in you must use --- login: root password: is last six of your MAC address of the printer. Do not include dashes and it is case sensitive. If any letters are present you must use upper case. Well I hope this helps.
Good Luck,
Daniel Mc.
Blade Computers