What you tried didn't work, regardless. Try using FEN tags as he suggested. Or, for the tag impaired, click on the "Insert board from FEN button."
But if you're talking about an offsite forum (the stoner one that was posted?), then obviously, this isn't going to work and you need to come up with your own solution.
RenderBoard(12,'rnbq3r/p1ppkpQp/1p1b1n2/4p3/8/3P1N2/PPP1PPPP/RNB1KB1R w KQ - 1 6' );
Looks like it comes in from this script: