Not clear if FPGA has been damaged by shorting HDMI outputs to ground or there are errors in UCF and/or hardware.

Probably a mixture...

Test firmware. Differential signal on connector pairs.

name period ctr-bit RJ45 HDMI1(left) HDMI2(right)
reset_or_clk 0.4us 4 good good freq. bad volts good(freq,volts)
trigger 0.8us 5 good bad bad
shutter 1.6us 6 bad(0V) bad bad
busy 3.2us 7 good good freq. bad volts bad

RJ45 - for