Of course it is not working out, why are you trying to add your own code to the installation script anyway? I mean, the original script is different from the code you posted above. Just reupload the original script and install it following the instruction, it shouldnt be difficult.
If you really wanna know the cause of parse error, you are not enclosing string within single or double quotes. This is the current syntax:
PHP Code:
$adopts = new PDO("31.170.167.208", "u296652253", "katy15");
Also I recommend you to change the database password, its insecure to showcase your password on a public forum like this one.