Ok. There are a lot of answers for your problem so here is a small list with points that could help(probably you have tried all them):
Get the latest aspi drivers(yes i know that clonecd has his own drivers, but this might help) get them from my site: http://come.to/Tom909
get the a working version of CloneCD that works with your computer, too, available at my site.
next step: check the sync data transfer box (should be marked, if not then mark it) at your system settings. The autorun function should be disabled! Do not install stuff like the plextor manager or other utils that could nerv. Get the latest firmware update for your recorder at http://www.plextor.com ord de
hmm, what else? Oh, yeah, try a lower reading speed and be sure that the disc you try to read is clean, cause the plextor devices are very sensitive concerning bad mediums. And get the latest ide bus drivers for your ide controller. I think that are all hints i can give so far. If you have more questions or need any help with clone then contact me: Tom909@t-online.de