Yes, usually that is all that it is. But you’re not giving us anything to go off of to assist you with. As I said, there could be a number of things causing this and we need more info. Please post a link to your site where we can see the error occurring and any other info you have on the error. A link to where you downloaded the theme will also help.
If you just uploaded a fresh copy of the theme than that most likely isn’t the problem, unless the theme is incomplete. I would check your rewrite rules in the .htaccess file as those could be causing it. It could also be the general settings for your site. Without any more info, that’s the best I can advise at this point.