what illegal op errors? are you using win2k? i’ve heard of some errors with that. but have never experienced any at all. even with adaptec easy-crap-creator. all tested under win98, winme, win2k, winxp. never had a problem with both burning software, probably never will. you probably have a conflict with something else, be it hardware, software, the weather, etc. coz my pc’s loaded with so many different software, and i still burn no problems.