Evolution can't create meeting, reports no backend for VEVENT

I can no longer create meetings or appointments from Evolution! This was happening in Oneiric, and now that I've upgraded to Precise it's still broken. An error is reported in the GtkInfoBar it pops up saying

      No backend factory for 'file' of 'VEVENT'

This is moderately horrid. My clients keep asking us to send the meeting invites, and we can't do it!

AfC

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: evolution 3.2.3-0ubuntu6
ProcVersionSignature: Ubuntu 3.2.0-23.36-generic 3.2.14
Uname: Linux 3.2.0-23-generic x86_64
ApportVersion: 2.0.1-0ubuntu3
Architecture: amd64
Date: Mon Apr 16 17:06:54 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111011)
SourcePackage: evolution
UpgradeStatus: No upgrade log present (probably fresh install)