Hey,
I dugg a little deeper and think I found the issue. When trying to initialize an Aperture parser, iMedia first looks for a key "ApertureLibrary" in com.apple.iApps which is gone on my system (I don't know if it previously was there, but any changing of "share previews with iApps" to always doesn't make it appear there again).
iMedia then looks at the com.apple.Aperture settings and checks two keys, "RKXMLExportManagerMode" and "LibraryPath". Whilst the first is present, the second one that is supposed to point to the library is called "XMLDataFilePath" and there is no "LibraryPath" present in the config (Aperture 3.2.2).
Does anybody know when the key for the library location changed? Once we have that info I can prepare a fix for this.
Robin