Reader 7.0.8 and IE 6.0

I have a web application that generates PDF files. Works fine. The web applicaion post data through HTTP to the user's browser.
 
2 situations :
 
- If application URL is [link=http://:8080/bla/bla/bla]http://:8080/bla/bla/bla[/link] PDF file is well displayed in the browser (Internet Explorer 6)
 
- If application URL is FQDN-like [link=http://.:8080/bla/bla/bla]http://.:8080/bla/bla/bla[/link] PDF file is not well displayed in the browser. In that second case the module