goodroi - 5:31 pm on Nov 29, 2010 (gmt 0)
it depends on how your website is setup. i have a feeling that the /?lc=en is a mirror of your index page. if that is the case you might want to try using a canonical tag. also make sure no links point to the duplicate page.
depending on your situation you could also use robots.txt wildcards aka pattern matching.