createClassInstanceForConnector and createClassInstanceForTreenode must do error checking on their queries and return false on error.
createClassInstanceForConnector and createClassInstanceForTreenode
must do error checking on their queries and return false on error.

fzadow/CATMAID,htem/CATMAID,htem/CATMAID,fzadow/CATMAID,fzadow/CATMAID,htem/CATMAID,fzadow/CATMAID,htem/CATMAID