Are you sure it is not a correct response to an underlying network problem - e.g. your PC - router or router - ISP connection dropping out?
Can you check for similar behaviour with IE or another browser?
Can you check connectivity by doing a continuous ping (ping -t) to a responding site (e.g.
BBC - Homepage) and examining the result for any timeouts that would indicate that your internet connection is dropping out?
To avoid irritation, try composing your posts in notepad (or similar text editor) until you have fixed the problem.
SD