I can't use phpmyadmin on windows 2012 server

I am having issues accessing phpmyadmin on windows server 2012 with iis 8. I downloaded phpmyadmin and moved it into the folder that localhost accesses, and renamed it to phpmyadmin. I changed the config.inc.php file to add a user and a pass and I changed the $cfg['blowfish_secret'] as well. However I get 500.19 error:

Detailed Error Information:
Module     DefaultDocumentModule
Notification       ExecuteRequestHandler
Handler    StaticFile
Error Code     0x800700b7
Config Error       Cannot add duplicate collection entry of type 'add' with unique key attribute 'value' set to 'index.php'
Config File    \\?\C:\www\phpmyadmin\web.config
Requested URL      http://localhost:80/phpmyadmin/
Physical Path      C:\www\phpmyadmin\
Logon Method       Anonymous
Logon User     Anonymous

I've changed the permissions on the phpmyadmin folder so that it should be accessible but I still keep getting this error. Can anyone help?