The best bet is when you're in a set or on a card, look to the column on the left - at the end is a link that says "See any inaccuracies?" click there and report it that way. In this case, it was a really easy fix for me, so I went ahead and fixed it (and moved the forum thread to the set - that's another thing, if you're writing about a specific set, please make a forum thread in that set's forum).
-- Dan --
Note: Please see my profile for more info regarding trading (section updated 3/4/2024). I have added a large portion of my inventory to the site, and currently have trading turned on (details are in my profile).