Unanswered topics in Apple about Aperture

When I try to activate a vault in Aperture, loading the Aperture library fails the next startup

Console messages:
Aperture[49612] Main Thread Exception in Aperture: Cannot remove an observer <archivepanelcontroller> for the key path "vaultStatus" from <rkarchive> because it is not registered as an observer.
No backtrace available.

and:
Aperture[50000] *** NSRunLoop ignoring exception 'Exception in Aperture: Cannot remove an observer <archivepanelcontroller> for the key path "isMounted" from <rkarchivevolume> because it is not registered as an observer.
No backtrace available.
' that raised during posting of delayed perform with target 0x13b4550 and selector '_delayedFinishLaunching'

Any hints why this is happening?

Accessing the Properties is still possible, but quitting fails, and the startup hangs just before closing the splash screen.
</rkarchivevolume></archivepanelcontroller></rkarchive></archivepanelcontroller>