The error below occurs during installation specifically when formatting:

Traceback (innermost last):
  File "/usr/bin/anaconda", line 438, in ?
    intf.run(todo, test = test)
  File "/var/tmp/anaconda-7.0.1//usr/lib/anaconda/text.py", line 1030, in 
run
    rc = apply (step[1](), step[2])
  File "/var/tmp/anaconda-7.0.1//usr/lib/anaconda/text.py", line 507, in 
__call__
    if todo.doInstall ():
  File "/tmp/updates/todo.py", line 1485, in doInstall
    self.fstab.makeFilesystems ()
  File "/tmp/updates/fstab.py", line 666, in makeFilesystems
    isys.umount("/mnt/loophost")
  File "/usr/lib/anaconda/isys.py", line 116, in umount
    mountCount[what] = mountCount - 1
TypeError: bad operand type(s) for -

Local variables in innermost frame:
what: /mnt/loophost
removeDir: 1

ToDo object:
(itodo
ToDo
p1
(dp2
S'method'
p3
(iimage
CdromInstallMethod
p4
(dp5
S'progressWindow'
p6

<failed>