Popup window problem

Hi,
I am having a page which opens a popup page when i click, first time everything is going fine. once the window is closed if again i want to open the popup window i am getting pagenot found exception in my parent page. Both my child and parent are jsf pages.

this is javascript in my parent form
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popup=window.open('PopupList.jsp', "popup",
"height=500,width=350,toolbar=np,menubar=no,"+ "scrollbars=no");

if (!popup.opener)
popup.opener = self;
popup.focus();
return false;
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My child window code

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window.opener.document.forms['form1'].elements['form1:field1'].value="aaaa";
alert("hello");
// document.forms['popupListForm'].submit();
window.close();
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