Hi,
My set up is a mid - 2011 macbook air running the latest version of PMS streaming to an Apple TV (wired) and iPad / iPhone (wireless). Some shows work fine but I am finding more and more that the video stalls and I get the Network too slow message.
Activity monitor on the mac shows that it's working to produce the video stream but the devices show the stalled video. After restarting the apps I still can't play the files until I reset the PMS. I have been through the forums and support pages and tried different set ups with the PMS and network without finding a solution.
The network seems fine as I can watch the same movies through VLC without missing a beat.