Windows Vista - The uploaded file could not be moved

Hello, I’m really newbie to Wordpress, and I’ve been struggling with this problem for 2 days, so please forgive that I also posted my question wordpress.org/support, but no response yet, so I’m reposting here.

This time I need to build my church website and many people suggests to use Wordpress.
So I installed Wordpress 3.0 on my Windows Vista under C:/xampp/htdocs/ -
I’m newbie as I told, so I thought I’d better test and get familiar with Wordpress on my windows before I move it to hosting company.
For now, the only requirement is that people can download (or play) the sermons. (so it means somebody(admin) needs to uploads the pastor’s sermons)
The site will likely grow having more menu in the future. I am using Twenty Ten theme for the site for now.

First I increase
max file upload size by changing .htaccess because most sermons are more than 400M.
Increasing max file upload size seems working, but the problem is that it says

The uploaded file could not be moved to C:\xampp\htdocs\wordpress/wp-content/uploads/2010/06

I don’t know how to solve this problem. I googled to find the solution, but the solution looks like changing owner of the 2010 folder in web host (Linux)
But mine is installed on Windows Vista, and I don’t know how to.

Would you please somebody tell me the solution?

Thanks,