Sounds to me like you are using Packet Writing... Nero's InCD to drag/drop data to your RW disc. You need to insure that InCD is installed or the InCD reader... That said, I feel like I should tell you that Packet Writing is unreliable and I do not use it. If you need to recover data on a RW disc done with Packet Writing software, consider investing $30 or so on
IsoBuster.
Also, not sure if your optical drives are capable of reading/writing DVD-RAM disc, but if you want to drag/drop files, that is the only way to go IMO.