I have had this same issue for the past 2 weeks, I have posted about it under the HD Channels topic, check it out.  They told me that I was switched to the 32/5 profile which is supposed to allow 3 HD streams and it was locking up the network.  They switched me back onto the 25/2 profile and same thing still happens.  Another tech is coming out tomorrow to see if they can figure something out.