I am haveing the same problem. and like Walkerandy have also had no luck with the velleman forums. mine will say it has programed correctly if I use an empty hex file.
also My pin 4 on the 18 pin socket it at about 8V witch I am asuming is either the problem or a symptom of the same problem. please could some one with a working unit measure the voltages on the soket while the switch is set to PROG.