There are indeed issues with Share functions in Windows 7 64-bit, since not all of the 64-bit drivers are yet compatible with 32-bit programs, and that could be part of your problem.
You can try updating to the latest version of Quicktime and see if that fixes it.
Otherwise -- until there are compatible drivers released -- you may need to use other programs (like Quicktime Pro) to convert your files to that codec.
What has me struggling is that I don't even have the Export function from the file menu available to me. I did with 7 before I upgraded, my next step will try to remove all traces of 8 and go back to 7. I tried a MPEG encoding from the Share tab, but the audio did not come out, probably a multiplexing issue. It just troubles me that I spent the money for the software and now I can't use it. Thanks for the quick replay I do appreciate it.
I tried to uninstall 8, looked in all the user folders, program folders, etc. but it semed to reatain all my preferences. I tried Google but no luck, anyone know any good guides to blow out all Adobe files from your computer & registry?
CCleaner and EasyCleaner are both free registry cleaning tools.
As you have found, the File>Export is dead in PrE 8. It should have been removed from the GUI.
Now, of multiplexing, there are several tabs for MPEG Export in Share: General, Video, Audio and Multiplexing. Even if you choose both Audio & Video in the General tab, you still need to choose DVD vs None in the Multiplexing tab. I think that is how things are laid out in PrE 8, but I am going from memory on what I have read - could be another tab in there. Still, one must set the type of Multiplexing.