Your burner doesn't support the discs you're using. You could try finding older 8x DVD+R blanks that your drive may burn, or you could just buy a new burner since they're pretty cheap nowadays. While you're at it, get rid of the CD-ROM drive too if you have no real use for it.
Well, with D/L burners going for <$30 now, perhaps it is time to upgrade. Any ideas why ISO burning had been working with this drive and these disks before I upgraded to 2.4.4.0?