While I was using Gnome and OpenBox on Ubuntu 12.04 Precise Pangolin, I got a lot of annoying error boxes saying “System program problem detected”.
To get rid of this error, all you have to do is uninstall a bunch of software. The packages that cause the errors are update-manager, update-manager-core and apport. Just do this and all the OpenBox errors on your Ubuntu 12.04 using Gnome will be gone:
$ sudo apt-get remove apport update-manager update-manager-core