Invalid MediaWiki API URL issue with Scripto

I've successfully installed Omeka 1.5 and MediaWiki.
http://diyhistory.lib.iastate.edu/index.php
and
http://diyhistory.lib.iastate.edu/MediaWiki/index.php

However, when I try to configure Scripto I'm getting "Invalid MediaWiki API URL"

When I replace http://diyhistory.lib.iastate.edu/MediaWiki/index.php with http://diyhistory.lib.iastate.edu/MediaWiki/api.php I get "forbidden" in the browser. Permissions are currently 777 on everything in MediaWiki.

I've looked in LocalSettings.php for anything that might disable the api. Everything is default though and there is nothing there.

What other places should I look to find out why this is not being recognized?

OK. I have an update to this.

I completely blew everything away (Omeka and MediaWiki) and started from scratch. I now have

http://diyhistory.lib.iastate.edu/deScribeIt/index.php
and
http://diyhistory.lib.iastate.edu/w/index.php

So Omeka and Mediawiki are in separate directories as was one suggestions on here.

I can now get to http://diyhistory.lib.iastate.edu/w/api.php

but am still getting that the "Invalid MediaWiki API URL" message. I've once again checked LocalSettings.php as per another thread.

This thing is a thorn in my side. Any suggestions?

I was wrestling with this for a couple of days, and found a solution that seems to work. Instead of using the fully qualified domain name, we just used "localhost". So maybe instead of

http://diyhistory.lib.iastate.edu/w/api.php

Try

http://localhost/w/api.php

or

http://127.0.0.1/w/api.php