Could be this one?
https://bugs.kde.org/show_bug.cgi?id=304763

Yes it looks very much like the Picasaweb crash.

A week ago I upgraded this install to Kubuntu 12.10 beta1 (KDE4.9.0) and the export to mail option returned to normal!
In the mean time other upgrades made a total reinstall necessary, I am now on KDE4.9.1 and the issue has not returned.
Gwenview and it's family are again working lovely

Based on the feedback from Gilles in that bug report, it would seem to be either a lack of implementation of functionality in Gwenview, or a binary compatibility issue in your installations. Please make sure your system is fully up to date, and that if you are using a PPA, that all installed KDE packages come from the same repository (whether the PPA or not).