If you want to get into grammar...
if i wanted to change the database i would have said changing the database
however here modifying is applied to the database itself
so therefore changing the database would be changing the current database in use, and modifying the database would be changing the data inside the current database
Changing:
Modifying: (assuming a DB is already selected)
Functionality. This is designed for forum admins, so they should know the user/pass/database
and as it's being distributed to forum admins, there is no reason to force them to make their own php page, or hard code in a password
if it were me i would add something that would give the option to save the password (using security through obscurity to prevent most people from finding the password), so that they're not forced to type it in all the time, or compromise their password by saving it if they feel that security through obscurity isn't enough