I found an answer here.
Try to open your FLA-file from a mapped drive instead of a network drive.
I got the same error when my file path was a network drive (\network\path), but dragging the file into an empty Flash instance from Total Commander made the file-path change to S:\myfolder\ and then the problem disapeared…
When your FLA-file is open, hold the mouse over the tap in the top to see what your file-path is.
I was trying to debug an Adobe Air desktop application for Windows in Flash CS6. The project was a clone of another project, with renamed files. I was getting “Application descriptor file cannot be parsed.” error when trying to debug the app (Ctrl + Shit + Enter). The error also popped up when I clicked on Adobe Air settings.
I tried creating a new Air blank project and debug but still the same error.
Then, I tried creating a new Air blank project in the default Documents folder created by Windows and debug it, and it worked! So I tried to debug my project again and it worked.
I was running Windows 8.1 on a Mac using VMWare Fushion.
Update 3 March 2017
I got the same problem. This time saving the files in Documents folder didn’t work.
I googled and found this post, moved the files to C: drive. That solved the problem.