Kudos to you, dentm42. I had the same issue and your suggestion worked perfectly.
Greg, great work on this plugin, I’m loving it so far.
Any chance you can add this note to the README for WPMU sites?
To elaborate, I’m adding a custom search-page to the site, so I want a URL like http://example.com/my-plugin-search but I DON’T want the user who is installing the plugin to have to do any extra work other than activate my plugin.