I'm not sure I get what you mean by " i have made the dump to create my postgres tables". Don't you just want to run tiki-install.php to worry about your tables?
I think you'll be the first to try Tiki with PostgreSQL on Windows. For Windows, maybe you'd prefer the more common and known to work EasyPHP install procedure.
The good page for logging in is indeed tiki-index.php.
Otherwise, what's your PHP memory_limit?
It's often easier to do troubleshooting live on our IRC channel.