I can tell you that any folder name that starts with _... (_vti_bin, etc.) is for use with Micro$oft FrontPage. If you don't use Frontpage, then you can safely turn off the Frontpage extentions in your CPanel. The cgi-bin folder is used for your cgi scripts. Not sure what software you installed, but I'm assuming that the chat folder is left over from that. And the images folder is a commonly used folder to store images.
There shouldn't be any file names that contain what you're asking. Hope this helps!