Firefox won't play .swf files offline

Simple enough, if I try to open a saved .swf file it'll open up the prompt "What should Firefox do with this file?" menu. If I select the open option, it'll just open a new tab and give me the same prompt.

I've tried un/reinstalling Firefox and updating my flash player plugin. The files play fine in IE but won't work in FF. Is there any solution to this?

The files play fine in IE but won't work in FF. Is there any solution to this?
Stop trying to open them in Final Fantasy.