Please make sure that you are entering the exact password that you specified in the Settings window. Note that the password is case-sensitive (hello is not the same as HELLO).
If you are not sure whether the password was specified upon the first use of Surfblocker, please try the blank password (enter nothing in the password box).
Please note that the full version setup password (registration key) has nothing to do with the Surfblocker password and it is valid only during the setup.
In trial version you can always use password "trial" (without the quotes). Please note that this does not apply to purchased version.