You need at least one linux partition. Format choices in the script are ext2/3/4. If you format it in gparted, that format will be overwritten by whatever you choose in the script. (The exception is if you choose the 'no format' option in the expert menu. I would advise against doing this unless you know what you're doing and have a good reason for it.)
Check the error log (/var/log/refractainstaller_error.log). If there's nothing of interest there, run the installer again, with the -d option for debug mode. (refractainstaller -d, or refractainstaller-yad -d).
If you have a single hard drive, and you're only going to have one system installed, you can use the simple install. It will make one partition on /dev/sda and put the boot loader in the mbr of that disk. (There might be a choice there, I can't remember.)
Oh, I think there are a lot of dbus errors every time, and I've gotten so used to ignoring them, that I forget they exist. They don't seem to interfere with the installation.
If you're using a version older than refractainstaller 9.1.3 on jessie or newer, there's a problem with the mount command. Use 9.1.4-1 from here -
http://sourceforge.net/projects/refracta/files/testing/ (or, if you wanted to change it yourself, find where it says "mount -t sysfs --bind..." remove the '-t sysfs' and do the same for the two similar lines with '-t tmpfs' and '-t proc'. The newer mount command in jessie pukes if you tell it the type.