I was having this problem as well with the Sony Bravia KDL-26M4000. I went into Picture Settings, Advanced Settings, and turned off the Light Sensor option. Voila- it works perfectly now! I couldn't believe that that was the problem. This post definately saved me a lot of troubleshooting time, as I never would have guessed the RF sensor was interfering!
I too encountered this problem shortly after getting a new Philips LCD model 42PFL7403D/F7. 7216 DVR did not respond to remote control any time TV was on --regardless of settings and/or distance (at least up to 6ft away). Never had any problem before with old CRT TV.
Replacing the 7216 with a 6416 seems to have resolved the problem.
??? Verizon techs: ???
Is there a sensitivity or light shielding problem with the 7216 that does not exist with the 6416 (e.g. is the internal physical design or layout different)?
In other words, is the older 6416 more immune to stray IR radiation than the 7216 due to physical placement, sensitivity, light shielding,etc of the IR sensor in the box?