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?

>>9
Already tried that.