As a user without access to the script you can't really know what settings are in play either. You need to contact the authors of the search you're trying to use. They can contact us if it's not working as they expect.
One possibility is that its not configured to allow intersections (@0).
We don't know what line 758 is as it is your application. Apparently it is trying to get a directory or file listing and failing. Most common reasons would be permissions or the file/directory does not exist. Someone familiar with your application would be needed to get more detailed.