Well let me respond to each one
1. File './asimplyb_PhotoP/pp_comments.MYD' not found (Errcode: 2)
Your comments table for photopost is either crashed or you deleted it. If it is crashed running this query in phpmyadmin should help you
REPAIR TABLE pp_comments;
If that does not help you can reinstall a comments table like so but doing so you lose any comments because your table is gone.
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2. Make sure to reupload your core php files except the config files. You have had a problem with your ftp client and one or more of your files are corrupt.