Why do you think it’s the host? Is Light-box a server related plugin? Does it use server resources to run/work? The Lightbox I know of is an AJAX application with absolutely nothing do with the server. AJAX is all browser.
If there’s a problem with a plugin, it’s the plugin not working right. Either WP not displaying the code right or the plugin isn’t printing the code right.
yerba# rm -rf /etc