Index: _whatsnew.html
===================================================================
--- _whatsnew.html	(revision 1902)
+++ _whatsnew.html	(working copy)
@@ -42,7 +42,8 @@
 	<p>
 		Fixed Bugs:</p>
 	<ul>
-		<li></li>
+		<li>[<a target="_blank" href="http://dev.fckeditor.net/ticket/1426">#1426</a>] Fixed the error loading
+			fckstyles.xml in servers which cannot return the correct content type header for .xml files.</li>
 	</ul>
 	<h3>
 		Version 2.6</h3>
Index: editor/_source/classes/fckxml_gecko.js
===================================================================
--- editor/_source/classes/fckxml_gecko.js	(revision 1902)
+++ editor/_source/classes/fckxml_gecko.js	(working copy)
@@ -32,10 +32,14 @@
 		oXmlHttp.open( 'GET', urlToCall, false ) ;
 		oXmlHttp.send( null ) ;
 
-		if ( oXmlHttp.status == 200 || oXmlHttp.status == 304 )
+		if ( oXmlHttp.status == 200 || oXmlHttp.status == 304 || ( oXmlHttp.status == 0 && oXmlHttp.readyState == 4 ) )
+		{
 			oXml = oXmlHttp.responseXML ;
-		else if ( oXmlHttp.status == 0 && oXmlHttp.readyState == 4 )
-			oXml = oXmlHttp.responseXML ;
+			// #1426: Fallback if responseXML isn't set for some
+			// reason (e.g. improperly configured web server)
+			if ( !oXml )
+				oXml = (new DOMParser()).parseFromString( oXmlHttp.responseText, 'text/xml' ) ;
+		}
 		else
 			oXml = null ;
 
Index: editor/_source/classes/fckxml_ie.js
===================================================================
--- editor/_source/classes/fckxml_ie.js	(revision 1902)
+++ editor/_source/classes/fckxml_ie.js	(working copy)
@@ -40,14 +40,19 @@
 
 		oXmlHttp.send( null ) ;
 
-		if ( oXmlHttp.status == 200 || oXmlHttp.status == 304 )
+		if ( oXmlHttp.status == 200 || oXmlHttp.status == 304 || ( oXmlHttp.status == 0 && oXmlHttp.readyState == 4 ) )
+		{
 			this.DOMDocument = oXmlHttp.responseXML ;
-		else if ( oXmlHttp.status == 0 && oXmlHttp.readyState == 4 )
-		{
-			this.DOMDocument = FCKTools.CreateXmlObject( 'DOMDocument' ) ;
-			this.DOMDocument.async = false ;
-			this.DOMDocument.resolveExternals = false ;
-			this.DOMDocument.loadXML( oXmlHttp.responseText ) ;
+
+			// #1426: Fallback if responseXML isn't set for some
+			// reason (e.g. improperly configured web server)
+			if ( !this.DOMDocument )
+			{
+				this.DOMDocument = FCKTools.CreateXmlObject( 'DOMDocument' ) ;
+				this.DOMDocument.async = false ;
+				this.DOMDocument.resolveExternals = false ;
+				this.DOMDocument.loadXML( oXmlHttp.responseText ) ;
+			}
 		}
 		else
 		{