$ dpkg --list|grep ia32
rc ia32-libs 20090808ubuntu11 ia32 shared libraries for use on amd64 and ia64 systems
I get roughly the same behavior. I started with the laptop docked, and when I undocked it actually switched to the internal screen OK. Then when I redocked I got the black screen, and when undocking again I was stuck with the black screen too (only showing a pointer that still moves with the mouse).
OK, with ia32-libs uninstalled:
$ dpkg --list|grep ia32
rc ia32-libs 20090808ubuntu11 ia32 shared libraries for use on amd64 and ia64 systems
I get roughly the same behavior. I started with the laptop docked, and when I undocked it actually switched to the internal screen OK. Then when I redocked I got the black screen, and when undocking again I was stuck with the black screen too (only showing a pointer that still moves with the mouse).