You may wish to try this: While running the Live CD, set up your partitions using the Administration > Partition Editor application. Make sure you have a proper swap file set up in addition to what other partitions you may need. You will then have the partitions ready for setting up manually when using the Ubiquity installer. I have seen similar problems, and this has seemed to help. Perhaps it will work for you, as well.
Currently running in the computer lab:
Linux Mint 17.2 MATE
Linux Mint 17.2 Cinnamon
CentOS 7 GNOME
Debian 8 LXDE