download autoagent switcher from this link:
http://kmext.sourceforge.net/macros/agentswitcherplus.7z
automatically changes the useragent to ff when it detects a site with bad sniffer..many popular sites with known bad sniffers are included and if you encounter a site that doesn't play nicely with kmeleon, simply add it to the blacklist by selected tools>user agent>add website and it will automatically use ff agent with that site.