There are times when plug-ins conflict with the system. I'm not an expert and don't know the exact reason, however, you can disable your plugins and find which one may be causing the issue, by adding a character or two (e.g.++) to the end of the folder name in your plug-ins folder (wordpress/wp-content/plugins/foldername++).
Generally, I tend to use plug-ins that are well rated and updated frequently. You can find that information on the plug-ins page of each instance, so that you may ascertain if the plug-in is well supported.
If a plug-in hasn't been upgraded to be compatible with 2.8.5 and the last time someone attended to it was over 100 days ago, it's safe to say that it may cause you a problem. Plug-ins need to be supported in a parallel track with WordPress core. If they aren't, there always seem to be some issues.
Try that solution. It can be a pain to do, but that's what I've been doing.