Great plugin, used it many times (local & remote), but have just run across an issue I've never seen. The file deploys flawlessly remotely, BTW, no issues.
Locally, however, I attempted to create a copy of a site, the install process quit during step 1 and didn't get to the Update (step 2) screen. It generated the site files & database, but I was not able to get to the login screen to finish the install, so I dropped the DB & deleted the site files to try again. Since then, each time I go to ~/site/installer.php both Chrome and Safari simply download a copy of the PHP install file and do not initiate the install.
I'm running MAMP on a Mac. Any ideas.