You'd first have to stream your camera to a site like YouTube.
To do that you'd have to install FFmpeg on your Raspberry Pi.
sudo apt-get update
sudo apt-get install ffmpeg
Once you've got FFmpeg installed you'd have to create a Youtube account and verify it. Once you've verified your account you can go to the encoder setup in the video ...
If you are looking to get access to the Pi with a floating IP (due to 3G dongle), I see two good options.
As ElefantPhace commented, Use ddns of some sort to create a statically available Domain name. This solution may not work if the 3G hotspot acts as a router and doesnt have port forwarding.
Run an OpenVPN server instance on your AWS Server and Connect ...
My guess is that this issue is occurring because a format is not specified in your server configuration, as is done here and here.
For example, you could edit the <Stream> to include the swf format: