Were the first 8 disks successfully burned? Burned but not read well in GSA-4082B? You used Emtec, Sky, Memorex and such media only?
If that's all true, make sure what media IDs those Emtec, Sky, Memorex media have. Make sure the media you use are at least good and compatible with your GSA-4082B before trying anything. The most widely compatible and available media for LG DVD writers are YUDEN000T02, RICOHJPNR02, MCC003, etc. for DVD+R. For DVD-R, TYG02, MCCRG02, MXLRG03, SONY08D1, etc.