I\'m using Octave 3.8 on Ubuntu 13.10 and \"fltk\" for graphics is not working well. So I always switch to \"gnuplot\" by commanding:
graphics_toolkit(\"gnuplot\
You add the command to your .octaverc file.
.octaverc
For more info: http://www.gnu.org/software/octave/doc/interpreter/Startup-Files.html