Longshot - are you positive this has solved your problem?
We also have a Roku and a Control4 HC250 in the field where every few days we got the lockup as well. Screen saver with no control, except with the Rokus own remote.
Roku has been on a MAC address reserve for months with no IP conflicts. The only thing I have noticed is that several neighboring networks were on the same wireless address, so I changed his thinking maybe that could be the problem.
However, still locks up from time to time.