I have a CS5.5 project that I have loaded into CS6. I have 6 sequences, when I try to export them, three work but when I try to open the export dialogue for the others nothing happens. Ctrl+M doesn't work either.The sequences play OK.
I have found that using the Media Encoder instead of Premiere works so I can complete the project. One thing that might be causing the problem is that I am getting the dreaded '.dll missing' error again. I will copy it to all the revelant folders again and see how it goes.
Also make sure all of your Windows Framework 4.0 and Visual C++ Updates are done with Windows update as well. If it's the codec Dll error I am thinking off, that will happen even if the file is preset if you dont have that done.