Is your internet connection working?
If not, fix your internet connection and restart Aperture, try again.
If it is not the network, you may have a locked or corrupted Aperture Preferences file.
Quit Aperture and try to remove the Aperture preferences from the user library as described here in the paragraph "Delete the User Preferences":
Aperture 3: Troubleshooting Basics: http://support.apple.com/kb/HT3805
Post back, if this does not help.
Regards
Léonie
P.S: Oh, I just saw this addition -
In fact, I can only edit and print the photos used in the album. The album itself does not do anything.
Then it may be necessary to repair the permissions and to repair the Library, using the Aperture 3 Library First Aid Tools; those are also described in the Trouble Shooting Support Article I posted above.
To use the Aperture Library First Aid tools press and hold the Option and Command keys as you start Aperture.
Start with "Repair Permissions", then "Repair Library".
Before you do any of this, make sure you have a working backup.