This has nothing to do with CUPS. It is a package installation/deinstallation problem of the Brother Debian package. Probably Brother's package is broken.
** Changed in: cupsys (Ubuntu) Status: Unconfirmed => Rejected -- printer cups wrapper cannot be found https://launchpad.net/bugs/85241 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs