Couldn't add an attachement to my mails

Wanted to answer an email and attach something. This didn't work. After clicking on "add atachment" ("Anlage hinzufügen" in german) an empty window opened (will add a screenshot to clarify what I mean).

As well it wasn't possible to drag and drop the file via the unity launcher.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: evolution 3.6.0-0ubuntu3
ProcVersionSignature: Ubuntu 3.5.0-17.28-generic 3.5.5
Uname: Linux 3.5.0-17-generic x86_64
ApportVersion: 2.6.1-0ubuntu6
Architecture: amd64
Date: Sun Nov 4 12:04:57 2012
InstallationDate: Installed on 2012-11-03 (0 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: evolution
UpgradeStatus: No upgrade log present (probably fresh install)