Make sure that you have the latest stable drivers for your system, in particular the IDE/SATA drivers for optical and hard drives. Make sure the system isn't defragmenting the hard drive in the background (could be scheduled, or automatic like in Diskkeeper's case). Make sure that UltraDMA is enabled if it is an available option. Make sure that no other programs are engaging in heavy disk access at the same time as burning. Make sure your version of Nero is patched to the latest. Make sure you have Windows updates. And you could also set your page file to be a static entity (a gig would be fine).
Hope that helps.