I’m sorry for the inconvenience.
If most of your problems appear after editing the username and password in the .PHP file, that means there was a mistake when editing them.
Are you using Notepad++ or Sublime text editors as explained in the first msg?
Anyway, since you are using the premium version, please, send us a support ticket using SUPPORT -> SUBMIT A TICKET
Our support team will look at your problem and solve it.