I am using internet via Proxy. I am unable to watch DivX movies online when I use internet through Proxy.
Third party proxies often filter out streaming content to reduce traffic and the load on the server running it.
If it's your internet providers proxy this shouldn't happen (unless it is in their policy) - in that case you might want to contact them or not use the proxy in the first place
How to Watch Videos Using a Proxy Site
maybe with tor