Website frontpage intermittently display html source code?

My website frontpage intermittently loads up it’s html source code instead of correct web frontpage. And if I click refresh in the browser it clears the html source code and display the correct page. It gives the following message too

[HTTP/1.0 200 OK Server: Lotus-Domino/0 Date: Wed, 18 Feb 2004 05:13:58 GMT Content-Type: text/html; charset=US-ASCII Content-Length: 3504 X-Cache: MISS from nme-pow-pr2.tpgi.com.au Connection: keep-alive ]

What is the problem and how can it be fix so that it doesn’t intermittenlty display the html source code.