I'm having the same problem as on the first page where all I have is a blank page show up. What can I do?
That guy said "The last update and this update share the same files as ones being edited which caused the confusion. Thanks for the help."
I have no idea what that means though. I am fairly new at working with phpbb.
EDIT - I restored the database and remodded all of the files back to 2.0.20, it's still giving me the same error. Can anyone help??
You made a mistake when you upgraded (typo, put chagne in wrong place, etc.). Openup your php error log (if you are on a host ask their support how to get access to your php error log) and it will probably tell you where the problem is.
Alternatively you could start with a fresh copy of 2.0.21.