What specifically are you trying to do - import, copy & paste or use the ArtSmart Object? Where is it failing?
Can you check the Console window (Shift-F10) and see if any warnings are shown?
In many cases the solution is to delete your symbolcache, which can be found in the prefs subfolder of the CINEMA 4D Preferences directory (the easiest way to get there is to open Edit > Preferences and click the Open Preferences Folder button, then navigate tot he prefs subfolder). If you delete that file and restart, C4D will re-generate the symbolcache automatically.