Sorry about that, I should have given more info.
I set up the partitions manually with the setup wizard, then formatted them with the format button in advanced mode. Had to reboot for it to take effect, then started install again and used the partitions, manually to install to. The install goes all the way along (blue progress bar almost to the end of its travel) then the error comes up about not being able to write the files to '/'
normally you will get this error if "/" is not big enough. No idea what is going wrong, it should work if "/" is at least 20GB. Are you sure you have this assignment and not used only 10GB for "/"? Alternatively, try to setup only two partitions, 2GB for Swap, and all the rest for "/".
good luck,
-p.