When Cafe World first brought new avatars into the game, there was a bug in their design because any time an avatar stood in front of a stove, the stove was literally blocked. The field around the avatar was too big and players couldn't click their stoves to make food until the avatars walked away.
There has been a fix to this problem as of April 7/8, 2011, the game developers have made it so this problem no longer exists. Players should now be able to click on stoves even when the avatar is standing in front of it.
For more information on the new avatars, visit the post New Avatars.