Error: Call to a member function getName() on a non-object in...

I completed a recent blog post, but when trying to view on the front end, I get the following error: 'Call to a member function getName() on a non-object in.....'. I found a similar issue in the forums that was caused by not having an author, but that is not the case with this post. This may or may not be related, but I have tried to update 5.0.13->5.0.26 several times. It appears to update successfully, but my dashboard still tells me to update. I have cleared the cache.