Install error with Drupal 7.15

Hi,
I've been trying to install drupal 7.15 on a vista machine using Apache 2.2, PHP 5.2.17 and MySql 5.5. Towards the end of the set up process I get a 500 internal server error.
The apache logs initially said that a favicon was missing so I got around that. Now I get the error:

File does not exist: C:/Program Files/Apache Software Foundation/Apache2.2/htdocs/drupal_7.15/admin, referer: http://localhost:8080/drupal_7.15/install.php?profile=standard&locale=en

I have mod rewrite on in apache but beyond that I'm not sure what is going wrong. There isn't anything in the drupal dir called admin, should there be?

Thanks.
Steve