First have you powered everything off and then back on and rebooted since the original incident? if not do that first.
You;re second post is confusing, you started a rebuild but you don't know if it finished? If you're getting the rebuild interrupted message it's most likely that the rebuild didn't finish. Stopping a rebuild in the middle is never a good thing and can easily make a bad situation worst. Before trying it again backup the library then you'll need to let it run, possibly overnight depending on the size of the library.
If the rebuild finishes and you still have problems try moving the plist file (~/Library/Preferences/com.apple.aperture.plist to the desktop and re-running Aperture.
Another thing you can try is to start Aperture while holding the shift key to defer preview generation. If you have a corrupt image file in the library that should help.
Both the plist and preview deferral are shown in Aperture 3: Troubleshooting Basics
Finally make sure Aperture is running ok. Start Aperture while holding down the option key. That will bring up the library choice window. Create a new library and let Aperture run on it.
I'd hold off on trying to manually rebuild the library just yet.