PuTTY tunneling breaks php generated pages on windows vista/7

I can easily create a tunnel under windows XP to tunnel 443-
"localhost:443" and then simply access the remote server pages
through the https://localhost URL. When starting with a plain
installation of Vista or windows 7 the same actions result in half way
broken pages (i.e. just like the connection to be reset during the
transfer of the page content) or pages not displaying at all.

Trunk Version of PuTTY,
Windows 7 default install
Remote Server: Centos 5.4 running FreePBX (a PHP application)
Tunneling: any chosen local host -> localhost:443 (on the server)

Where is the problem?