maxima plot problem on OS X lion



I have maxima-5.21.1 and gnuplot-4.2 installed on my macbook with
 OS X lion.when I issue 
        plot2d(sin(x), [x, 0,  %pi]);
from maxima prompt, no output window shows up.  Before I upgraded 
to OS X lion. a Aqua window contains the plot would show up.

I do see a maxplot.aqua file in my directory. However, it is empty. other file ,
maxout.gnuplot, maxout.gnuplot_pipes and maxout.xmaxima all seem
 to have the correct contents.

I also checked that in my .maxima directory, I have a maxima-init.mac 
that contains the line:

set_plot_option([gnuplot_term, aqua])$

When I start gnuplot from command line, it says that terminal type is aqua.

Any one here experience this issue?  Please help.

-Michael