2) Which "Classified" module are you using? Which version?
3) To delete the "xf21_vp_reports" table, you would have to go to the phpMyAdmin and delete it manually.
Please note: Publisher should have no problems with the "vp_reports" table.
The "vp_reports" table is part of "VideoTube", but because "VideoTube" is not maintained on XOOPS anymore, use instead "XoopsTube". I'll try to test it this weekend on PHP7 and XOOPS 2.5.8 and provide an update.
4) When you talk about "uploading videos by the user" - you mean a physical file, or only a link to something else?