If you have enabled Gzip compression on your website (this is done from your cpanel -> Optimize Website), you may experience some issues with videos not playing in IE and Chrome. More about Gzip you can find here:

http://www.tmdhosting.com/kb/web-site-down/slow-website/enable-gzip-compression/

You may simply disable the Gzip compression and the issue shall be resolved, however there is another way to make the videos work with Gzip enabled. If you have all our swf files in one folder, then go ahead and create an .htaccess file inside that folder with the following:

Options +FollowSymLinks
RewriteEngine on
RewriteRule . - [E=no-gzip:1]

This  code will only disable gzip for the swf file type. So that there is no compression or cache of the file types. You can also use it on a per folder basis