hey
still you are in problem with the isp programmer.please send the latest and the exact circuit which you are using now.also the ic details which you used.i have made a development kit for RX2 series and circulated more than 15 among my friends.i didn't face even a single failure till now.

and while using flash magic wait for 10-15 sec. after the message "finished" display on the botttom window

also try to read the boot vector and status byte before programming the chip.make sure the values are FC and 00 respectively.

better luck
Saji