Forum "Advertising" section blank in AdminCP
 

Sorry if this has been address, but my forum search didn't reveal any instances of this exact problem.

My upgrade from 3.8 to 4.0 went well without any major hitches, but when I attempt to go to "Ad New Add" in the Advertising subsection of the adminCP, it leads to a totally blank page. The admincp/ad.php file, which it apparently points to, was uploaded to my server just fine, and beyond that, I can't think of what the issue might be.