#2 URL not found

[doclip]

I followed all the steps provided in the install.php file.
When I open http://localhost/~username/flexmonitor for the first time, it starts with step 1 and asks to press next.
By pressing next I get the following error:

Not Found

The requested URL /Users/username/Sites/flexmonitor/installation/index.php was not found on this server.

I am installing this on a Mac and the web server files are all under /Users/username/Sites

thanks for your help.