open new window problem

<%= link_to document.name, :controller => 'member',
:action => :show_attachment, :id => document.id,
:popup => ['new window', 'width=800, height=700, left = 450, top = 100,
resizable, scrollbars=yes' ] %>

but it opens the file in the same window.
Any ideas why?
  

I've found that IE (surprise) is a bit strange when it comes to poup
titles. If the title contains any spaces then it will open in the same
window. I've observed this behaviour on IE6 so, just in case, no more
spaces in my popup windows' titles.

regards,

javier ramirez