Modelio refuse to start and complains about GTK+

Modelio refuse to start and show me

Gtk-WARNING **: This process is currently running setuid or setgid.
This is not a supported use of GTK+. You must create a helper
program instead. For further details, see:

http://www.gtk.org/setuid.html

Refusing to initialize GTK+.

A powerful implementation for singly linked list in java with new functions

Here is an implementation for singly linked list in java
I also implemented some function -that are not in the books about data structures-
This function removes or adds elements at specific place, returns an element from a specific place and so on