3D plot is not drawn by the use of MapleNet's Image Generation

I am using MapleNet14 on Mac OS X Server 10.6.4. 

I tried to draw 3D plot by the use of MapleNet's Image Generation.

But the following URL that is sample code from document does not 

produce 3D plot.

http://localhost:8080/maplenet/imaging/image?maple=plot3d(x^2%2By^2,x=-1..1,y=-1..1)&width=400&height=400

Error messages are

  MapleNet JSP Error

  com.sun.opengl.impl.macosx.CGL.createPBuffer(IIII)J

  Please try again.

Other plot, for example,

http://localhost:8080/maplenet/imaging/image?maple=plot(sin(x),x=0..2*Pi)&width=400&height=200

works well. 

The environment of my server is as follows;

OS: Mac OS X Server 10.6.4

MapleNet: 14

Maple: 14.00

Java: 1.6.0_20

Tomcat: 6.0.24