Re: Buddypress installed on Windows Server
You really should search before posting, rather than have us do it
this is most likely a mod_rewrite / .htaccess issue o in this instance on a windows server a lack of mod_rewrite.
It is a question that crops up many times, try this link for some info and follow it’s links as well.
The WP Codex also has advice on url rewriting in particular on windows servers.