Why doesn't $row->path output its value?
It is a known issue with views_php.  You should be able to access the field information through the $data variable though. If you have Devel installed just run dpm($data) in place of your code above and see how to access the field information.

For what it is worth, it is generally considered bad practice to store php code in the database. I would suggest taking a look and seeing if there is any way you can accomplish what you are after with a template file override or some other means.  If the only thing you are trying to accomplish is concatenation of those 3 fields with labels, you can do that with a regular views 'custom text' field and the tokens views provides.