Mongrel and content type

I set up an apache2 + mongrel clusters.

Everything is working fine except that IE Explorer when I try to see a page of my site it tries to download it instead of showing it. Firefox and Safari are working fine, I have also checked the content type in the headers sent by the server and they are correctly set to "text/html". The url the application is serving are without any extension e.g. "http://myserver/page"\.

I guess that there is a problem with content-type setting but I can't really realize what I have to configure and why it's happening only in IE.

Any idea?