I've been having issues with my stock 411s. Trying to do burns with Imation media (RITEKG03) I always (95%) get skips and stalls near the end of a disk. I'm new to DVD burning so it took me a while to get up to speed on some of the tools. I found out about kprobe and it's showing a strong ramp in PI/PO errors on the last 20% or so of the disk, and big single spikes throughout (perhaps 30 or so spikes in the first 80% before it all goes to h3ll in the last 20%). Sorry, forgot to save my scans, but I'm getting into the 500's for PO which isn't good 
For testing I've been burning using decrypter (latest version). I started with burning at MAX, but then changed to 2x, and then tried setting 1x (but the burns seem to do a 2x minimum?). Occasionally I've gotten a usable burn (based on kprobe) but never with really good kprobe numbers.
Anyone have any ideas?
BTW: Anyone know if there is a known bug in kprobe? Sometimes if I let it run overnight, when I come back it has a few error popups about (from memory) "canvas doesn't allow draw" or some such and the system is generating out of resource errors requiring a hard reset. This is under XP (SP1) with the screen saver having kicked in).
Edit: I am using the latest firmware