os: win98
jdk: 1.5 b11 above but works fine with b10;
There was no effect on setting either Disable d3d flag(-Dsun.java2d.d3d=false) or Disable ddraw flag (-Dsun.java2d.noddraw=true);

run the following sample code:
import java.awt.*;
public class A {
public static void main(String[] args) {
Frame f = new Frame("Testing");
f.setSize(400, 400);
f.setVisible(true);
}


you will get Exception in thread "main" java.lang.NullPointerException
at java.awt.Window.init(Window.java:247)
at java.awt.Window.<init>(Window.java:275)
at java.awt.Frame.<init>(Frame.java:401)
at A.main(A.java:8)


See attached platform infos for two win98 (one with multimon)