It sounds like the problem you are having is related to starting the Signup Form generator after modifying the config.php file manually. The best way to get this message to stop is to:
1. Remove the information you added from the config.php file manually, and then restart the program.
2. Delete your CCSFG_0.0.2 folder, and replace it with an unmodified version by re-downloading it.
3. Log into the program through your browser using the credentials you have in the config.php file, click the "Access Credentials" button, and use your correct username and password there. This will write the correct information into the config.php file, thus allowing you to successfully authenticate your login credentials with Constant Contact.