Since from the screenshot it would appear that you're able to see the CDROM device I'd drop to a terminal and run this command to find out the path that the CDROM device is being mounted at.
As others have said most of the distros are using /media
as some form of the mount point for removable media. I'm on Fedora 19 but this method should work the same for you. Using this command in a terminal will show you the device & path that's being used to mount the removable media:
$ mount | grep media
Example
$ mount | grep media
/dev/sr0 on /run/media/saml/Fedora 19 x86_64 type iso9660 (ro,nosuid,nodev,relatime,uid=1000,gid=1000,iocharset=utf8,mode=0400,dmode=0500,uhelper=udisks2)
From the above we can identify that the device being mounted is /dev/sr0
and the directory where this device is being mounted is /run/media/saml/Fedora 19 x86_64
.
So to change to the directory:
$ cd /run/media/saml/Fedora 19 x86_64