Most users complain about the error pop-ups rooted from the ads attached to their Yahoo! IM clients. Turning off from the registry is the best way shun them. In the registry, [HKEY_CURRENT_USER\Software\Yahoo\Pager\YUrl] Set or add these values, Messenger Ad = * Webcam Upload Ad = * Webcam Viewer Ad = * Webcam Viewer Ad Medium = * Webcam Viewer Ad Big = * Change Room Banner = * Conf Adurl = * Chat Adurl = * Edit the file \Program Files\Yahoo!\Messenger\Cache\urls.xml, erase all the contents and leave 2 double quotes (” “), save it then mark as read-only.