Is it a new drive? The reason I ask is you mention sending it in for repair. Repair, unless its under warranty is not really a viable option as a brand new drive costs about £35 and it would cost more in someones time to fix it.
I'm not really up on the Sony rootkit, I have heard of it but have no idea if it can cause this. It could be hardware or it could be software. Initially I would attempt to delete and reinstall your burning software. If there is a second PC available you could remove it and try it on that, that at least would confirm whether its hardware or software.