I can't tell whats wrong, but I can tell you not to worry about switching it. Most TVs will take of the switch from 1080i to 1080p by themselves. Sometimes better then the dvd player or game system does.
I own a samsung 46' F series LCD tv, i can run call of duty 4 on the ps3 on 1080i resolution fine. But when i set it to run on 1080p, the screen flickers and its unplayable.
Could anyone tell me what is wrong? i am not sure if it's the cable or the tv.