many threads exist on this subject.
The vblicense number is at the top of the vb
config file as well as the cookie prefix is within that file also.
I would suggest you run install again and make sure the license number is correct in the config and on the next to last step of install make sure you enter the correct cookie prefix which is normally bb
You would then be able to get into the admin control panel. Those two variables are so important in vb3 cause the password cookie is an encrypted string made up of the user password, salt, vblicense number and cookie prefix so those must be correct for proper authentication.