File could not be opened

I have a Fusion composition, and when I try to open it I get a message that says "The file could not be opened as a composition". I can't figure out why. Any ideas on how I can get the composition to open? It was working fine before.

Below the main error message ("The file could not be opened as a composition") it should output a detailed error - something like

[string "Composition"]:5: unexpected symbol

What does it say in your case?