Optiarc 5170/7170 reading problem

Hi,
I bought NEC/Optiarc 7170 and replaced it later with 5170 and I have same problem:
I have Windows XP. When I put blank DVD-R media - then any operation on the burner takes long time (==stuck). For example: Nero InfoTool, or even File browser trying to access the burner. If I remove the media - it works great.
Now, I took blank DVD+RW -and it was OK. I burned it with Nero, and listen to this: Burning was OK, but verification got stuck. I can’t read this media on this burner, but I can read it without any problem on my other DVD reader.
I have firmware 1.11, and windows DVD driver SW.
Can someone please help me ?

Thanks

Yossi