I am sorry for the late reply since it is weekend here.
I have checked your site and it seems like the theme file for discuss_signature is there. I suspected that the issue is with your site caching. Can you try turn off your site caching and test again this issue. If this issue is still persist, please do inform us back.
Please replace the attached file in: ../media/com_easysocial/apps/fields/user/discuss_signature/discuss_signature.php. As for Easyblog Biography, you might want to update the app from http://www.stackideas.com/apps . Please give it a try. Hope this helps.