I think with the WP 3.9.1 upgrade an incompatibility was introduced. I'm running the latest Twenty Eleven theme.
This is the error message: Fatal error: Cannot use object of type WP_Error as array in /home/etc. ...line 535.
Upon inspecting line 535, I noticed it was trying to get file size of uploaded podcast, so I overrode that value in the newest post. The post would load properly, but then the RSS file was corrupt, which defeats the purpose.