This is what I got from synaptic when I tried to install emacs22 and uninstall emacs21

Selecting previously deselected package emacs22.
(Reading database ... 139856 files and directories currently installed.)
Unpacking emacs22 (from .../emacs22_22.1-0ubuntu5_amd64.deb) ...
(Reading database ... 139869 files and directories currently installed.)
Removing emacs21 ...
emacs-remove emacs21
remove/ecb: purging byte-compiled files for emacs21
remove/cedet-contrib: purging byte-compiled files for emacs21
remove/cogre: purging byte-compiled files for emacs21
remove/jde: purging byte-compiled files for emacs21
remove/semantic: purging byte-compiled files for emacs21
remove/ede: purging byte-compiled files for emacs21
remove/eieio: purging byte-compiled files for emacs21
remove/speedbar: purging byte-compiled files for emacs21
emacsen-common: Handling removal of emacsen flavor emacs21
emacsen-common: purging byte-compiled files for emacs21
remove/elib: Handling removal of emacsen flavor emacs21
remove/cedet-common: purging byte-compiled files for emacs21
Removing emacs21-bin-common ...
Removing emacs21-common ...
Selecting previously deselected package emacs22-el.
(Reading database ... 138751 files and directories currently installed.)
Unpacking emacs22-el (from .../emacs22-el_22.1-0ubuntu5_all.deb) ...
Setting up emacs22 (22.1-0ubuntu5) ...

Setting up eieio (1:1.0pre4-2) ...
install/cedet-common: Handling install for emacsen flavor emacs22
Loading 00debian-vars...
No /etc/mailname. Reverting to default...
Loading /etc/emacs22/site-start.d/35elib-startup.el (source)...
Loading /etc/emacs/site-start.d/50cedet-common.el (source)...
Loading /etc/emacs/site-start.d/50dictionaries-common.el (source)...
Loading debian-ispell...
Loading /var/cache/dictionaries-common/emacsen-ispell-default.el (source)...
Loading /var/cache/dictionaries-common/emacsen-ispell-dicts.el (source)...
Loading /etc/emacs/site-start.d/50eieio.el (source)...
Loading /etc/emacs/site-start.d/50jde.el (source)...
Loading /etc/emacs/site-start.d/51ede.el (source)...
Loading /etc/emacs/site-start.d/51speedbar.el (source)...
Loading /etc/emacs/site-start.d/52semantic.el (source)...
Loading /etc/emacs/site-start.d/53cedet-contrib.el (source)...
Loading /etc/emacs/site-start.d/53cogre.el (source)...
Loading /etc/emacs/site-start.d/55ecb.el (source)...
"/usr/share/emacs22/site-lisp/cedet-common/" added to `load-path'
Error while loading 55ecb
Cannot open load file: eieio
emacs-package-install: /usr/lib/emacsen-common/packages/install/cedet-common emacs22 emacs22 failed at /usr/lib/emacsen-common/emacs-package-install line 30, <TSORT> line 2.
dpkg: error processing eieio (--configure):
 subprocess post-installation script returned error exit status 255
dpkg: dependency problems prevent configuration of ede:
 ede depends on eieio (>= 1:1.0pre4-1); however:
  Package eieio is not configured yet.
dpkg: error processing ede (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of semantic:
 semantic depends on ede; however:
  Package ede is not configured yet.
 semantic depends on eieio (>= 1:1.0pre4-1); however:
  Package eieio is not configured yet.
dpkg: error processing semantic (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of jde:
 jde depends on eieio (>= 1:1.0pre3-6); however:
  Package eieio is not configured yet.
 jde depends on semantic (>= 1:1.0pre3-6); however:
  Package semantic is not configured yet.
dpkg: error processing jde (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of cedet-contrib:
 cedet-contrib depends on semantic (>= 1:1.0pre4-1); however:
  Package semantic is not configured yet.
dpkg: error processing cedet-contrib (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of cogre:
 cogre depends on semantic (>= 1:1.0pre4-1); however:
  Package semantic is not configured yet.
dpkg: error processing cogre (--configure):
 dependency problems - leaving unconfigured
Setting up emacs22-el (22.1-0ubuntu5) ...
Errors were encountered while processing:
 eieio
 ede
 semantic
 jde
 cedet-contrib
 cogre
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install.  Trying to recover:
Setting up eieio (1:1.0pre4-2) ...
install/cedet-common: Handling install for emacsen flavor emacs22
Loading 00debian-vars...
No /etc/mailname. Reverting to default...
Loading /etc/emacs22/site-start.d/35elib-startup.el (source)...
Loading /etc/emacs/site-start.d/50cedet-common.el (source)...
Loading /etc/emacs/site-start.d/50dictionaries-common.el (source)...
Loading debian-ispell...
Loading /var/cache/dictionaries-common/emacsen-ispell-default.el (source)...
Loading /var/cache/dictionaries-common/emacsen-ispell-dicts.el (source)...
Loading /etc/emacs/site-start.d/50eieio.el (source)...
Loading /etc/emacs/site-start.d/50jde.el (source)...
Loading /etc/emacs/site-start.d/51ede.el (source)...
Loading /etc/emacs/site-start.d/51speedbar.el (source)...
Loading /etc/emacs/site-start.d/52semantic.el (source)...
Loading /etc/emacs/site-start.d/53cedet-contrib.el (source)...
Loading /etc/emacs/site-start.d/53cogre.el (source)...
Loading /etc/emacs/site-start.d/55ecb.el (source)...
"/usr/share/emacs22/site-lisp/cedet-common/" added to `load-path'
Error while loading 55ecb
Cannot open load file: eieio
emacs-package-install: /usr/lib/emacsen-common/packages/install/cedet-common emacs22 emacs22 failed at /usr/lib/emacsen-common/emacs-package-install line 30, <TSORT> line 2.
dpkg: error processing eieio (--configure):
 subprocess post-installation script returned error exit status 255
dpkg: dependency problems prevent configuration of ede:
 ede depends on eieio (>= 1:1.0pre4-1); however:
  Package eieio is not configured yet.
dpkg: error processing ede (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of jde:
 jde depends on eieio (>= 1:1.0pre3-6); however:
  Package eieio is not configured yet.
dpkg: error processing jde (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of semantic:
 semantic depends on ede; however:
  Package ede is not configured yet.
 semantic depends on eieio (>= 1:1.0pre4-1); however:
  Package eieio is not configured yet.
dpkg: error processing semantic (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of cedet-contrib:
 cedet-contrib depends on semantic (>= 1:1.0pre4-1); however:
  Package semantic is not configured yet.
dpkg: error processing cedet-contrib (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of cogre:
 cogre depends on semantic (>= 1:1.0pre4-1); however:
  Package semantic is not configured yet.
dpkg: error processing cogre (--configure):
 dependency problems - leaving unconfigured