I use prototype less then 2 month and so sorry if my question looks
too banal.
On the one of the server I used I can't receive responce by using IE
6.0 (I,ve not check another versions).
I written easy example to show the problem.

Example is there: http://testajax.royalbuild.ru/

The code bellow:

index.html
-----------------

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/
TR/html4/strict.dtd">
<html>
<head>
<title>Test HTTPRequest</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<script type="text/javascript" src="/prototype.js"></script>
<script language="javascript" type="text/javascript">
function JStest()
{
new Ajax.Request('/aj.php',
{
method:'get',
onSuccess: function(transport){
alert('onSuccess .. OK');
var response = transport.responseText || "no response
text";
alert("Success! \n\n" + response);
$('message').innerHTML = response;
},
onFailure: function(){ alert('Something went
wrong...')}
});
}

</script>
</head>
<body onload="JStest();">
<div id=message></div>
</body>
</html>

aj.php
-----------
<?php
echo 'Test complete';
?>

This example isn't works in IE 6.0 in this server, but works in Opera
and FF.
The phpinfo is here: http://testajax.royalbuild.ru/phpinfo.php
If it neсessary the headers scrinshot generated by Web Development
Helper (http://projects.nikhilk.net/Projects/WebDevHelper.aspx) is
here: http://testajax.royalbuild.ru/headers.gif

Thanks for attention and advice how to solve this problem