cannot access install.php (step 6)

Hello,

I have completed #1-#5 in the 5 minute wordpress install.
Now I am stuck on #6 trying to access the install.php.
The browser keeps asking me to download the file rather than opening it…. and I don’t know why.
Below is the address of my file. I really appreciate it if anyone could help me a bit. Thanks a lot.
http://bert.art.yale.edu/~lanlanliu/wordpress/wp-admin/install.php