Is it cold where you are and have you brought the DVD discs from a warmer place? It could be condensation on a warm disc.
Can you play an audio CD in the DVD drive? If that doesn't work then you could have a faulty DVD drive.
Are the DVD map discs originals or copies? The EU discs have a copy protection scheme, I'm not sure if the US discs do as well.
Can you play an audio CD in the DVD drive? If that doesn't work then you could have a faulty DVD drive.
Are the DVD map discs originals or copies? The EU discs have a copy protection scheme, I'm not sure if the US discs do as well.