====== apt-get cannot remove or install crappy package (solution) ======
after the installation of a package that was probably not made for your exact system especially when you forced the installation to ignore dependencies it might happen that you jam up your apt package manager. it gets even worse if you decide to manually delete the installed files. 

i ran into this problem after installing the pt9500 cups wrapper and then deleting the installed files manually. 

whenver i did something with apt-get be it install or remove a program i got this error: 

<code>
Removing pt9500pccupswrapper ...
/var/lib/dpkg/info/pt9500pccupswrapper.prerm: 3: /usr/local/Brother/PTouch/pt9500pc/cupswrapper/cupswrapperpt9500pc: not found
dpkg: error processing pt9500pccupswrapper (--remove):
 subprocess installed pre-removal script returned error exit status 127
/var/lib/dpkg/info/pt9500pccupswrapper.postinst: 3: /usr/local/Brother/PTouch/pt9500pc/cupswrapper/cupswrapperpt9500pc: not found
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 127
Errors were encountered while processing:
 pt9500pccupswrapper
E: Sub-process /usr/bin/dpkg returned an error code (1)
</code>

in order to get rid of this package i could not even use 
  apt-get remove cupswrapperpt9500pc
it showed the same errors. 

your first try after this should be 
  sudo dpkg --remove --force-remove-reinstreq pt9500pccupswrapper

if you are lucky this will help
if not, your apt is seriously broken.. 

now i think your only chance is to delete the dpkg stuff yourself.. i did it like so: 

first i searched for anything that sounded like "pt9500" in my /var/lib/dpkg directory
  /var/lib/dpkg$ find * | grep "pt9500"

this showed a list of files in the info/ folder
<code>
info/pt9500pccupswrapper.postrm
info/pt9500pccupswrapper.postinst
info/pt9500pccupswrapper.prerm
info/pt9500pccupswrapper.list
info/pt9500pccupswrapper.preinst
info/pt9500pccupswrapper.conffiles
</code>

which i then removed: 
  mkdir /tmp/info
  sudo mv info/pt9500pccupswrapper.* /tmp/info/

just in case my system or apt crashes even worse afterwards i copied it to a directory that i created in /tmp where it will stay until i reboot my system. 

now update your apt-get database and install missing dependencies: 
  apt-get -f install

this resolved my problems