reads NO DISK


In Runtime
when i copy a dvd then put it im my dvd player it reads no disk and the same for when put in the computer,
the burn process goes well and there definetly is something burned on the disk from looking underneath the disk.

its not specific dvds that have the problem because it happens to the dvds that i have just made a copy of like a few hours earlier and my dvd-r is supposed to be very compatable. the dye on the disk is G04, my burner is Toshiba SD-R6112 and i use nero 6.

most of the time it works fine but when it doesnt im ended up with coasters.

does anyone why this is happening?