I have a similar problem:
My Acer Aspire comes with the HL-DT-ST DVD +-RW GWA4164B drive. Initially, I could use it as intended for reading and writing both CDs and DVDs. Suddenly, I could no longer use it for reading and writing DVDs (but still for reading and writing CDs).
I have upgraded to the 1.05 firmware without success (whenever I put an empty DVD in the tray the device says "No disc inserted"). It seems as if the drive has lost its ability to handle DVDs.
Any guidance on how to correct this problem is much welcome (alternatively, tips of a good replacement drive are also welcome)