some turn-on troubles

i'm trying to install my amp.  There is really not a good place to ground my wire.  All the metal in the trunk area is painted, real thin, no bare metal at all.  I grounded it to the best place i thought possible.  I connected my remote lead to a wire called pcont, however, there is also a wire called ext cont.  Anyone know the difference?  the manual says they are for amplifiers, well no sh*t manual, thank you very much but what's the difference. 

Bottom line, i spent a good amount of hours running wires and my amp won't turn on.  I saw it blink one time, but taht was it.  All the fuses are good, nothing has blown.  my guess it is the ground or the remote wire.  I have it grounded to the best spot i can find and i have tried both of the pcont and ext cont wires, and all i've gotten was a short blink from the amp. i was a little delirious and red with anger that maybe it didn't even blink at all.  anyone have any troubleshooting solutions or know a good place to ground a wire on a 2004 civic coupe?