maybe you could upload them to a server or maybe your isp has given you some space in which to host webpages, upload it there and give the person the link to download the video files
You email them like you do anyother file. Just attach them to the message
Although are you trying to use a free web based email service such as hotmail? There is a 10MB limit on the attchments, the video may be larger than that and that is why it isnt working.