I use Nero 6,usual things to check out I've found are stopping background programs running, so means coming offline and turning off antivirus and firewall and anything that might be allowed to update itself by periodic online checks, a bit drastic but you could go into msconfig startup tab and untick all ticked items, but usually just stopping all the uneeded things running is enough, all them icons by the clock, find out what they are and stop them.
I usually defrag the hard drive before burning as the captured video is usually fragmented, then reboot the pc.
Nero makes a temporary file of what it's going to burn, which it deletes usually after burning, so you need free hard drive space for that alone, usually need to allow twice the space of the thing you are burning and ideally a contiguous block of free space, so defrag and have plenty of free space, a decent cpu and fair amount of ram.
You could always do the burn in two stages, as the all in one transcoding and burning is causing problems. In Nero rather than burn to dvd select the burn as image to hard drive, play the image file later and if that's OK burn that as an image file in Nero to a dvd and burn at slowest speed, dvd rw won't be that fast anyway.