have just bought a vivastar rs111 writer, and also purchased some bulkpaq generation 3(r2) dvd-r disks from another supplier. The disk that came with the writer a vivastar 4.7 gb general / 120mins worked great first time, but whilst trying to the bulpaq purple disks in nero i got power calibration errors and ulead dvd factory 2 kept asking me to insert a dvd-r media when there was one in there. Can anyone clear this up? and does anyone know of disks which do work. Apparently the drive is recognised as a matshita lf-d310 in nero, any help would be appreciated thanks!!