SageTV playback probem

[whobday]

My Sage box had been running smoothly for years. I use a HD-100 extender for the bulk of my playback. I recently switched from Comast to Fios TV service. I made no changes to Sage other than the EPG data switch. I simply plugged my Fios boxes into the server the same way I had the Comcast boxes connected (S-Video, fwiw). Ever since the switch certain recordings "lock-up" the extender. It just stops working, no video, no audio, just the twirling icon. I can do a soft reset by hitting the power button on the remote, however, the server becomes sluggish at that point. looking at the server, the SageTV process is pegged at 100% utilization and has to be reset. If I convert the recording from mpg2 to mpg4, it converts correctly and is viewable. I'm a bit stumped. Any insight?