The famous javascript Access Denied error from callout

System

Hello All,

I am encountering the famous javascript 'error: Access is Denied.' when a new window is opened through a call out.

I have already checked below possibilities and those are not a problem:

execute permission for the script,
write permission for WORKAREA,
the availaibility of the opened page from the opener page,
The domain of the opened page and opener page.

The line numbers suggest that error is nearby below lines:

-----------------------------------------------------
document.forms['singleedit'].action = url;
document.forms['singleedit'].target = calloutWin.name;
document.forms['singleedit'].elements.iw_callback_var.value = callbackVarName;
----------------------------------------------------------

Code is attached:

1) .jsp page is the opener window page
2) .ipl is the opened window