Let's say you configure the plugin to show 2 posts and 2 excerpts. If I have a single sticky post it displays 3 posts and 2 excerpts.
Perhaps you need to have an "Include Sticky Posts" option and use that in your call to query_posts (use the ignore_sticky_posts' parameter in the query).
But then if you're doing that then maybe you also want an "Include Sticky Excerpts" option and process each post appropriately too. Hmm.
The quick-and-dirty fix is to add this line above the wp_query on line 78:
$q .= '&ignore_sticky_posts=1';