I went from partition/drive selection to "custom partitioning" and deleted all the partitions on /dev/hdc. After this, I committed and was left with this backtrace:
Traceback (most recent call last):
File "/usr/bin/ubiquity", line 120, in ?
install(sys.argv[1])
File "/usr/bin/ubiquity", line 54, in install
ret = wizard.run()
File "/usr/lib/python2.4/site-packages/ubiquity/frontend/gtkui.py", line 266, in run
self.process_step()
File "/usr/lib/python2.4/site-packages/ubiquity/frontend/gtkui.py", line 736, in process_step
self.gparted_to_mountpoints()
File "/usr/lib/python2.4/site-packages/ubiquity/frontend/gtkui.py", line 869, in gparted_to_mountpoints
self.size_widgets[-1].set_text(
File "/usr/lib/python2.4/site-packages/ubiquity/frontend/gtkui.py", line 471, in set_size_msg
size = float(self.size[widget.split('/')[2]])
KeyError: 'hdc1'
/var/log/syslog