When you install the plugin you get a message which advises permalink structure of /%postname%/
When you install WordPress you get advice not to use %postname%, %category%, %tag%, or %author% for pretty urls, but %post_id% would be ok.
If you follow the links to http://ottopress.com/2010/category-in-permalinks-considered-harmful/ you find that a bad url choice is saving up trouble for later. WordPress will write huge numbers of .htaccess rules and eventually get very slow.
Is there any conflict here? Does this need some clarification?