this is a classical case of bad browser detection that sniffs brand instead of engine. there is nothing special on that website..either css or js that requires gecko 1.9 and cripples 1.8, not to mention that they accept opera 9.
even if you use kmeleon 1.6 alpha which uses the same engine as firefox 3.5 you will still get that message.. an extension called agent switcher has been updated to auto change the ua to opera string with that site..you can download the extension from this link:
http://kmext.sourceforge.net/macros/agentswitcherplus.7z
see faq to install:
http://kmext.sourceforge.net/help.htm
or extension manager
http://kmext.sourceforge.net/kem.htm
but my recommendation is override them with css since that is just a layer 'screening' the content..simply removing that layer and you'll have full access to the site..you can still install the agent switcher extension which will come handy for other sites with stupid sniffers, but my recommendation is this:
first open your usercontent.css file from this menu:
edit>configracion>custom stylesheet/css (will vary in spanish kmeleon)
this should open usercontent.css in your notepad.exe
once it's open add those lines to the file usercontent.css(copy and paste brown below)
@-moz-document url-prefix(http://actualidad.rt.com/)
{
div[id="jr_overlay"]{display:none!important}
div[id="jr_inner"]{display:none!important}
}
save the file and restart kmeleon(you must restart kmeleon after)
now you can surf normally to rt without worrying about the useragent