If another drive on the same system does the same thing, then maybe try swapping out the flat IDE cable for a fresh one.
Also, can you download and run Nero InfoTool (or find it in the Toolkit, if you have Nero installed), and post the text output for us?
That should tell us if anything screwy is going on software-wise. Try swapping out the IDE cable first, though. And double check the jumper on the back of the Pioneer, to make sure it’s position corresponds with the drive’s position on the cable - Master if the 107 is connected to the end of the cable, Slave if it’s connected to the middle.