a problem about plotting



Hello, I am new to Maxima.

I have installed the Gnuplot, and I encountered some problem as follows when
plotting.

(%i39) load(draw);
(%o39) /usr/local/share/maxima/5.16.3/share/draw/draw.lisp
(%i40) draw2d(explicit(u^2,u,-3,3));
Maxima encountered a Lisp error:


UNIX error 32 (EPIPE): Broken pipe, child process terminated or socket
closed

Automatically continuing.
To reenable the Lisp debugger set *debugger-hook* to nil.

What's wrong?