Posting Animate Files to this forum issue

Was trying to post a question about a problem. But now I have to post a question as to why the forum won't allow me to upload an animate file to the post. It keeps saying:

"Correct the highlighted errors and try again.

• The attachment's recover_character rigging_b.fla content type (application/octet-stream) does not match its file extension and has been removed."

I received file from my student through email. I've tried opening, saving a copy, renaming and saving to different locations on the computer but it keeps saying the same thing. Any assistance would be great.