Popup window not understanding size

I have a page where there are three links. If you click on the first link it launches a popup window and to it’s correct size. Then if you click on the next link it pops open the link in the old popup, which is the incorrect size.
In order for it to popup in the correct size all other windows have to be closed before you pop open a new popup.
How can I get this to work?
You can see what is happening on this **link **

Thanks, :toad: