solution for change password popup

Hi,

I need to create a similar screen such as SU01 transaction. i donot know how to get the popup which u get when u click on the change password button on the application tool bar.

I have copied the screen 400 from the original transaction into my program and tried to call the screen when i click on change password button. But a dump is coming.

Can u help me with a solution in getting that popup screen.