[Plugin: Multiple Category Selection Widget] Can’t be used if you are not using permalinks?

Just trying this out as it appeared perfect for our needs.

But… any search brings up a “Not Found, The requested URL was not found on this server.” message and a permalink type address.

So I guess that without a major rewrite this won’t work on default ?p=123 type sites.

Pity…

http://wordpress.org/extend/plugins/multiple-category-selection-widget/