I have the same problem with 10.8.4 on a 2008 Mac Pro. I have a fix, sort of. The only thing that works is reinstallin ML over itself and going through all the updates. Takes me about 20 minutes. It has recurred from time to time and the same fix works. Something breaks periodically, and I can't figure it out. Permissions, deleting plists, etc. does not fix it.
More on this one. The problem appears to be a conflict between 10.8.4 Security Update 2013 and newer versions of Skype. Reinstalling the Security update temporarily fixes the problem but it comes back. Reinstalling the update and uninstalling Skype fixed it for me. It's been about 5 days so far. If it comes back, I will re post. I found bits and pieces on this one and got there by trial and error. No guarantees.
It is not related to Skype. I completely removed it. The problem did come back without it. Reinstalling the Security Update 2013 fixes the problem, temporarily. Also I have noted that when Quicktime misbehaves, so does saving files in Office 2011 for mac. Reinstalling the security update fixes that problem as well.