Mike
There is no reason that if you try to log-in through the 'Add to Database" link
that it will not accept the same username and password that you successfully
log-in to view the Parish Records. Be it the Parish Records or the Surname
sections you are logging in from the registration checks the same list of
username and passwords.
The only thing I can think of is that you are using the "remember me" function
in your browser and it is automatically inserting the incorrect details,
probably an old out of date username or password you once used on this site.
I suggest that you first log-in to the Parish Records and then navigate to the
Surnames section, because once you are logged from either you have access to
both.
If you still have difficulties after doing what I suggest, please go to the
Contact us Page and use the "Help and Support" form and we will try and work out
what is going wrong.