Can't Export Session

Hello, Audition Friends.

When I export my session, nothing shows up in the folder I try to save it to; external hard drive or same laptop. Along the exporting process, a window pops up and says that one or more file types are unknown?

This doesn't happen with any new or old sessions. They export just fine. 

Adobe suppport has been unable to help me after a lengthy time on chat. I senior support person can't get back to me til after the weekend. Thanks for any ideas! Or even a suggestion on other work arounds.