unable to mount any disk space: "could not find "/mnt/stateful_partition".

Basically, i recently installed crouton for ubuntu on my toshiba chromebook to be able to play games ect. When i first entered ubuntu using unity there were no default programmes such as firefox ect, which i had to manually download. On my folders there is a 3.3GB and 11GB drive that is unable to mount that comes up with the error message: "could not find /mnt/stateful_partition"
please check spelling and try again. there are also two "Root-A" folders, that when i click on them it says: unable to mount root-A, one or more block devies is holding dev/mmcblk0p5. The other Root-A file says: error mounting: mount: wrong fs type, bad option, bad superblock on /dev/mmcblk0p3
missing codepage or helper programme, or other error,
in some cases useful info is found in syslog - try dmesg | tail or so

im really confused as to why this is happening. I also apprently not permitted in certain areas, esecailly when trying to access folders.