Multiple functions for several joins in a query - how to do it?

[eluser]titanite[/eluser]
Dear Mischevious: You are WAY too advanced for me... I'll study your method carefully and find out why you do it that way.

Federico: Thank you so much for your help! It was exactly what I needed to learn!

However, I have run into one error. In the cases where $info->director_2 is NULL, I have the "Message: Trying to get property of non-object" error message.

When director_2 is not null, I have his name printed.

Why is there such an error?

Code:

<h3>Directed by: &lt;?php echo "$info->director_1_firstname $info->director_1_lastname"; ?&gt;&lt;?php if($info->director_2_firstname !== NULL){ echo ", $info->director_2_firstname $info->director_2_lastname"; }  ?&gt;</h3>