xeraa:
I'm getting the same errors as you are on a fresh install on Vista + Apache 2.2 + PHP5 + Mysql.
It won't be because you're running on localhost:8080 that the rewrite failed - I installed a virtual host and my apache is running on :80. It's probably something in the script itself that can't handle it properly.
I just tried installing on XP + Apache 2.0 + PHP5 + Mysql and I'm getting this error when installing on install.php:
If you receive a fatal error, refresh this page to continue the installation
# Creating 'tutorial/_config.php'...
# Creating '.htaccess' file...
# Building database schema...
Fatal error: Cannot redeclare class HTTPResponse in D:\websites\test\sapphire\core\control\HTTPResponse.php on line 143