Add these 2 options to your Device section in your xorg.conf and reboot
Option "DynamicTwinView" "false"
Option "ModeDebug" "true"
Run this in a terminal, this will save a file listing all the available modes your X server has created, the 'mode pool'.
sed -n '/- Modes/,/- End/p' /var/log/Xorg.0.log | sed 's/.*(0)://g' > $HOME/Desktop/modes.txt
Add the name off the modes you want to your Screen section of xorg.conf, like you posted in the Subsection part. This might be trial and error because you obviously have modes in your modepool which your tv doesn't like.
If you reboot and now run..
This should list all the modes you've just specified, basically what you see here is what modes a game would see are available to it. Make sure you can switch to each e.g
xrandr -s 1024x768 -r 60
Something else you could try if that doesn't work, add the following to your Screen section of Xorg.conf, this should only allow modes originating from information read from the EDID chip in your screen, this might stop you ending up with invalid modes in the pool.
Option "ModeValidation" "NoVesaModes,NoXServerModes,NoCustomModes,NoPredefinedModes,NoUserModes"