I have a 111L Pioneer, and have found it to be a very good drive. It should be able to handle those 16x disks with no problems. You might try changing the burning speed of DVDDecrypter from Max to 8x.

Or take the output from RipIt4Me and use ImgBurn, which is the updated burning engine from DVDDecrypter. But it really sounds like the disks are being burned correctly, they're just not recognized by your player.

You say you are using -R disks, not +R 16x?