If you have lost your BIOS settings this may indicate that there is an issue with the battery on the motherboard or that you are not running the latest BIOS as per
ECN-0204. It would probably be best to check both of these things before proceeding as otherwise the same thing may happen again.
Depending on what console and therefore keyboard you are using it is important to ensure that NumLock is turned off when typing the password. Otherwise
68340 may become
6834*, you can also try this in case it was entered wrongly initially. Normally if you get an error message like the one you describe you can reboot to get back to the normal BIOS password screen.
Instructions for setting the BIOS up correctly can be found on the
Titan Troubleshooting page.