Well "Content-type:text/html" is called a header and shouldn't be visible on any page. If it is, that may be the cause of the problem.
I've only ever seen headers being printed out when scripts were run on a Windows? server. If that's what you are hosted on, I suggest you contact their tech support and see if they can correct the matter. I have no idea what would need to be done.
If you're not on a Windows server, I have no idea what would cause the header to be printed out, sorry.
Dan O.
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