trying to burn an iso in Brasero, this is all I get under select a disc to write to: "Replace the disc with a supported CD or DVD. It is not possible to write with the current set of plugins." Can't find any online help, can't check integrity because Brasero says that there is no available disc to check.
Mount command tells me: /dev/sr0 on /media/cdrom0 type iso9660 (ro, nosuid, nodev, ut f8, user=edwin)

Doesn't this mean that the dvd is mounted? And if so, why can't Brasero see it? Is Brasero just a bad program to use for burning iso files?

Read only means it's not a blank disc.
Try a blank disc.