Cita:
Iniciado por all-ill 
¿Puedes indicar el formato resultante del URL a la que redirige Location? Es decir, la dirección a la que intenta redirigirte (ya sea apuntando lo que pone en la barra de direcciones o usando echo antes de usar header).
Puede ser útil revisar el registro de errores del servidor, ubicado generalmente en alguna subcarpeta de /var/log/, para determinar el problema (si es por alguna regla del .htaccess u otro tipo de error...)
Creo que lo encontré:
[Tue Jun 29 16:53:54 2010] [warn] pid file C:/xampp/apache/logs/httpd.pid overwritten -- Unclean shutdown of previous Apache run?
[Tue Jun 29 16:54:48 2010] [notice] Digest: generating secret for digest authentication ...
[Tue Jun 29 16:54:48 2010] [notice] Digest: done
[Tue Jun 29 16:54:49 2010] [notice] Apache/2.2.14 (Win32) DAV/2 mod_ssl/2.2.14 OpenSSL/0.9.8l mod_autoindex_color PHP/5.3.1 mod_apreq2-20090110/2.7.1 mod_perl/2.0.4 Perl/v5.10.1 configured -- resuming normal operations
[Tue Jun 29 16:54:49 2010] [notice] Server built: Nov 11 2009 14:29:03
[Tue Jun 29 16:54:49 2010] [notice] Parent: Created child process 4080
[Tue Jun 29 16:54:52 2010] [notice] Digest: generating secret for digest authentication ...
[Tue Jun 29 16:54:52 2010] [notice] Digest: done
[Tue Jun 29 16:54:53 2010] [notice] Child 4080: Child process is running
[Tue Jun 29 16:54:53 2010] [notice] Child 4080: Acquired the start mutex.
[Tue Jun 29 16:54:53 2010] [notice] Child 4080: Starting 150 worker threads.
[Tue Jun 29 16:54:53 2010] [notice] Child 4080: Starting thread to listen on port 443.
[Tue Jun 29 16:54:53 2010] [notice] Child 4080: Starting thread to listen on port 80.