http://www.portforward.com has many walk-throughs on how to forward ports on an array of different routers. Look on there. Of course, you have to had administrative access to the configuration page of your router. If it's a work router or something, then you might be out of luck. But you can always just default to the HTTP download. The forwarded ports are only needed to download via torrent (provided i'm not mistaken)

In that case you need to tell your router that the ES program should be allowed to use the ports.
How to do that, depends on what router you have. If good, the manual of your router will describe
how you can do it. For most routers its enough to allow the program, however, some will require
to tell the exact port that needs to be opened for it.
Good luck!