If you replaced it with exactly what you wrote, then yes, you will get a parse error because you are missing the end parenthesis.
At the top of each vb page is something like this:
PHP Code:
define('THIS_SCRIPT', 'online');
That defines the page name. So, if you are going to have the tab highlight because you are on a specific page, that is the best method to use. But, you can use other valid conditions also as long as they don't interfere with the conditions to have another tab highlighted.