HiI've often noticed that the GTK miniiso hangs at the final message "unmounting file systems" after you tell the FE to complete installation and reboot. If i then switch to VT1 i can see than /etc/init.d/postbaseconfig fails at step S95 (umounting filesystems). To make the reboot happen you then have to do ctrl+alt+canc, anyway after reboot the newly installed system works regulary.
ciao Attilio