Home Sharing stopped working in iTunes 11.04

This turned out to be a network issue with the router. It was fixed to a particular channel (which was probably being used by another router) and the devices were not consistently connecting. I fixed it by switching the channel to "auto" on the router. For those of you for whom this doesn't work, try picking individual channels (this can sometimes work)...it is slightly annoying, though, since all of the devices have to reconnect each time you switch the channel.