Dropped frames in nerovision

I’m trying to capture 720x486 mpeg2 in Nerovision using an AIW 7500. It seems to capture without dropped frames for the first 27 minutes but after which (around 1.6 gig file) it starts to drop frames like crazy. It does this on a predictable basis. I’m trying to eventually use the direct to DVD+VR capture feature. Has anyone experienced or solved this problem with Nero? Otherwise, I’ll have to ditch this program for something that works.