These are just audio samples which are read incorrectly.
The cause of these errors is usually bad media. A solution is to use different media or decrease the drive’s speed.
If the number of data errors is not too high you probably won’t hear them because the internal error correction routines of the drive should be able to fix them. Nero CD Speed detects them by comparing the read bytes with the known data from the test disc.” quote taken from Nero CD Speed.
If you are doing Audio Extraction, it will be done in sequential form, which as you can see by your results is fine, so you should have no problems. I suggest when extracting audio do it at a slow speed 8x, 12x or 16x if you are in a hurry and you should get good quality results. I have the same drive as you and I don’t have any problems with Audio that I have extracted using the method described above and my test results are similar to yours. If you let the test run to end it would of given you results for speeds from 1x to 16x, choose one of the OK speeds for your audio extration.
I say this though this drive is not as good as my old 48246S at doing anything except playing DVD’s of course.