What does this mean for me? You will always be able to play your favorite games on Kongregate. However, certain site features may suddenly stop working and leave you with a severely degraded experience.
What should I do? We strongly urge all our users to upgrade to modern browsers for a better experience and improved security.
We suggest you install the latest version of one of these browsers:
Kongregate is a community-driven browser games portal with an open platform for all web games.
Get your games in front of thousands of users while monetizing through ads and virtual goods.
Learn more »
Make sure it is a true .swf file not a .exe or any other file that you renamed to .swf because it would say invalid.
Try saving the .swf file again to see if that helps or save it as different name(the file might be broken or corrupted).
I hope that helps.