Upgrade Error

Following this:
http://omeka.org/codex/Upgrading

Omeka encountered an error when upgrading your installation:

Migration file '018_schemascrub.php' does not follow proper naming conventions.

What do you suggest? How do I fix? How do I roll back?

upgrading from 1.2

You've left files from your previous version in the application/migrations directory.

Delete that directory and unzip 1.3.2 again.