Hey Dan,
Thank you for your purchase! I know had a look at the install script and you are right. I made one super stupid mistake.
Normally the prefix is not a problem when you are using the standard joomla functions. And I'm using them, but I don't know why I have written jos_ for prefix instead of jos_ - you see jos_ gets replaced with your prefix and jos_ stays the same
Sorry about that.
I will need you to unzip the zip package that you have downloaded, then open it and find the install.comment.php file and then on line 81 you wil see the following code:
$query = 'INSERT INTO ' . $database->nameQuote('jos_comment_setting') . ' VALUES'
change it to
$query = 'INSERT INTO ' . $database->nameQuote('jos_comment_setting') . ' VALUES'
I'll update the installation package myself today so if you can wait several hours you don't have to make the above chages.
Cheers,
Daniel