Currently Being ModeratedOct 10, 2012 1:50 PM (in response to kroes)
Aperture 3.4.1 is sandboxed, and apparently it can no longer use external clients and plug-ins that are not sandboxed. Outlook and Entourage need to be updated to comply with MAcOS 10.7.5 and 10.8.x to work with Aperture 3.4.1.
See this lengthy discussion: Re: Aperture email sharing (Outlook) not working since upgrade to mountain lion
And send feedback Apple - Aperture - Feedback to Apple and Microsoft.