window.opener help needed

[Filiz Duman]

I am opening a new page (child) window. As soon as a item is selected in the
child window,it passes it back to the parent window and closes itself:

parent window code:
newwindow = window.open("0to100.htm" , "popup1",
"width=500,height=500,screenX=200,screenY=200,top=200,left=200",
"alwaysRaised");

Child window code:
window.opener.document.forms["SixCos"].elements["ef"].value = name;
self.close();

So far there is no problem, and it works OK.

But my problem is, if I want to open a package with values passed, rather
then a static .htm page my window.opener does not work and returns NULL.

newwindow =
window.open("http://xxx/pls/xxx/is_interface.sixcosbw?curbw=0&maxbw=2&maxefo
raf=1010&mineforaf=0" , "popup1",
"width=500,height=500,screenX=200,screenY=200,top=200,left=200",
"alwaysRaised");

Any ideas, why window.opener in the child window fails ?