package hylafax-server (not installed) failed to install/upgrade: subprocess installed post-removal script returned error exit status 1

I tried to remove the config (using Synaptic) and got this. I investigated and I think that the problem seems to be the
/var/spool/hylafax directory:
administrator@JohnLaptop:~$ sudo rm -r /var/spool/hylafax
rm: cannot remove directory `/var/spool/hylafax/etc': Device or resource busy
administrator@JohnLaptop:~$ ls -al /var/spool/hylafax
total 12
drwxrwxr-x 3 uucp uucp 4096 2010-03-07 12:32 .
drwxr-xr-x 12 root root 4096 2010-03-07 11:18 ..
drwxr-xr-x 0 root root 0 2010-03-07 12:13 etc

As published in similar installer issues this concrete one might be related with the bind mount the init script does of /etc/hylafax to /var/spool/hylafax/etc. We've noticed the init.d script does not umount it correctly which might explain why that directory can not be deleted.
In any case, passed this error other installer issues arise due the contents of the same directory being compared agains /etc/hylafax. Some kind of strange loop seems to be there""

The problem is that hylafax-server was not unmounting correctly /var/spool/hylafax/etc. This has been fixed in versione 6.0.4-10. Please get that package from Debian or wait until it gets propagated to Ubuntu.

This bug was fixed in the package hylafax - 2:6.0.5-5ubuntu1

---------------
hylafax (2:6.0.5-5ubuntu1) natty; urgency=low

  * Merge from debian unstable. Remaining changes:
    - debian/patches/901_fchmod-prototype.patch: glibc now includes
      a fchmod prototype which doesn't match hylafax's. (Closes: #565001)
  * Upload should fixes: (LP: #372605, #476098, 595610)

hylafax (2:6.0.5-5) unstable; urgency=low

  * Remove /etc/default/hylafax when puring package (Closes: #607064)

hylafax (2:6.0.5-4.1) unstable; urgency=low

  * Non-maintainer upload.
  * Fix "installation fails": check for existence of /etc/mtab before using it
    (closes: #604221).
  * Fix "prompting due to modified conffiles which were not modified by
    the user": write to /etc/default/hylafax only if it doesn't exist
    (closes: #603429).
 -- Artur Rona <email address hidden> Wed, 22 Dec 2010 20:10:59 +0100