Have the blocks disappeared from your profile page? Bl.ocks.org will stop trying to find valid blocks if your last 100 gists don't qualify as a block. If you want to fix it, just create a valid block. (A valid block is defined on the about page.)
xxxxxxxxxx<html><body> <svg width='800' height='500'> <text x='400' y='250' style='text-anchor: middle;'> This is a valid bl.ock </text></svg> </body></html>