Solution given in Blink Codes link. Quote from Plextor:
TROUBLESHOOTING: Blink Codes Actions
Please follow all steps outlined below:
Re-boot your computer. Check again.
Make sure the disc is not upside down or scratched
- If this is a CD-R or CD-RW disc, try another one from a different manufacturer
If you still get blinking LED lights after going through the troubleshooting process your drive is most likely defective. Click here for return/repair information. Please reference attempting this test procedure on the RMA request form.