I spotted the following files in my 404 log.
File not found errors
/wp-content/plugins/collapsArch/img/collapse.gif
/wp-content/plugins/collapsArch/img/expand.gif
Looking at the plugin the correct folder for these icons would be collapsing-archives
A quick review of the code, I also see there are a couple of other places where the plugin folder is hardcoded.
See: http://codex.wordpress.org/Function_Reference/plugin_dir_url and http://codex.wordpress.org/Function_Reference/plugin_dir_path
