Error:document.body returns null or not an object

[deepthirohini]

Hi friends,
I am using IE6. I am having the problem during navigation of the page.
See i am having the parent window.

Parent Window -> Click -> Child window -> Click download

The scenario is
from the parent window i am having the button click whenever i click that button i open the child window and then click download. At that time the IE6 does not download any thing it tells the ERROR: document.body returns null or not an object.

But the same scenario is working in IE7, firefox.

Thanks,