Upgrade 1.5.3 to 2.2.2 404 Error

I am upgrading from 1.5.3 to 2.2.2, and at the last step am encountering a database upgrade error. It cannot find the upgrade file path:

The requested URL /wwi/exhibit/admin/upgrade was not found on this server.

There is no upgrade/ directory in the Omeka root. What am I missing?

Thanks,

Jeff

There's not supposed to be an upgrade folder.

That error message looks like a standard Apache one, meaning Omeka isn't even running at that URL. Are you sure you have the .htacces file in place, with any changes to the RewriteBase intact?