Well it doesn't seem like a problem with your hdmi cables, as the one from amp to tv works ok, and the one from the ps3 works ok when connected directly to tv.
Have you tried connecting the ps3 to the other hdmi inputs on the amp? In case it's that particular hdmi input.
Try the v box in the input the ps3 is connected to. Try and narrow down where the problem is- tv, amp, or ps3.
Also, you could check / redo your ps3 display and sound settings. Try the soft reset with it connected to the amp - from standby hold down the I/0 button till it gives a few peeps, it'll set itself to lowest resolution. Hopefully you'll get a picture then and can redo your display settings.
Try a factory reset of the amp - hold down power button for 5 secs or so, it'll say "clearing... cleared". Could be a setting on the amp that's been changed.
I've never heard of that error message on ps3, sounds like it might be a message from your tv.
Bit vague but i hope that helps