I seem to be having some trouble with the OTA module too.
Watching tv live is not a problem, its when I record something and then try to watch it I get an error every 2 minutes or so "portion missing due to lost signal" (not exact wording.) but it only appears to have 1-2 seconds of the show missing with each error.
Watched the Simpsons live without a problem and had watched Family Guy that I recorded and that was loaded with errors. (Wife had recorded Grey's Anatomy off the antenna and had the same problem.)
Signal is in the 73-85 range and doesnt drop out when we are watching it live.
Do you recall the signal strength before the module..(did you have a 622, etc?)