Admin account compromised

[Dave]

The script you linked is called a "PHP Shell" or "PHP Backdoor", it allows people to interact with the server/database/any files on the server in any way they want.

Now the question whether there are any backdoors left is hard for us to answer. All it takes is one line of code to act as a backdoor, this can be hidden in any of the thousand(s) of files vBulletin uses.