I'd wager the disc is in a UDF packet format, something like when one formats a CD to act like a floppy.
Try this in a console to mount it (first make sure the mount location exists):
mount -t udf /dev/hdc /mount/location -o ro
..where hdc is your DVD drive (hdb or hdc or hdd or whatever) and /mount/location is a folder to mount the disc on.
If this fails, it would likely be better and simpler to re-burn a/the DVD using a standard burn, as Vista defaults to something not necessarily simple to read when doing that drag & drop stuff.
Packet-writing IS supported by Linux, and isn't complicated, but the Vista CD's are just 'weird'