Eu sei, não estou dizendo que ninguém está nervoso não, pedi paciência só porque sei que essa situação está um saco mesmo.
Bom, segue a resposta:
Segue listagem das suas conexões MySQL abertas neste instante:
31837 dbr_dfbr localhost dbr_phpbb1 15 Query INSERT INTO phpbb_search_wordmatch (post_id, word_id, title_match) SELECT 4731321, word_id, 0
31860 dbr_dfbr localhost dbr_phpbb1 15 Query INSERT INTO phpbb_search_wordmatch (post_id, word_id, title_match) SELECT 4731322, word_id, 0
31791 dbr_dfbr localhost dbr_phpbb1 40 Query INSERT INTO phpbb_search_wordmatch (post_id, word_id, title_match) SELECT 4731320, word_id, 0
31686 dbr_dfbr localhost dbr_phpbb1 58 Query INSERT INTO phpbb_search_wordmatch (post_id, word_id, title_match) SELECT 4731319, word_id, 0
31633 dbr_dfbr localhost dbr_phpbb1 79 Query DELETE FROM phpbb_search_wordmatch WHERE post_id IN (4731311)
31320 dbr_dfbr localhost dbr_phpbb1 174 Query INSERT INTO phpbb_search_wordmatch (post_id, word_id, title_match) SELECT 4731318, word_id, 0
31241 dbr_dfbr localhost dbr_phpbb1 185 Query INSERT INTO phpbb_search_wordmatch (post_id, word_id, title_match) SELECT 4731317, word_id, 0
31294 dbr_dfbr localhost dbr_phpbb1 185 Query INSERT INTO phpbb_search_wordmatch (post_id, word_id, title_match) SELECT 4731316, word_id, 0
31045 dbr_dfbr localhost dbr_phpbb1 259 Query INSERT INTO phpbb_search_wordmatch (post_id, word_id, title_match) SELECT 4731315, word_id, 0
30493 dbr_dfbr localhost dbr_phpbb1 0 Query INSERT INTO phpbb_search_wordmatch (post_id, word_id, title_match) SELECT 4731311, word_id, 0
30618 dbr_dfbr localhost dbr_phpbb1 0 Query SELECT word_id FROM phpbb_search_wordmatch WHERE word_id IN (85, 486, 540, 615, 632, 1129, 148
30800 dbr_dfbr localhost dbr_phpbb1 0 Query SELECT m.word_id FROM phpbb_search_wordmatch m, phpbb_search_wordlist w WHERE w.word_text IN (
31904 dbr_dfbr localhost dbr_phpbb1 5 Query INSERT INTO phpbb_search_wordmatch (post_id, word_id, title_match) SELECT 4731323, word_id, 0
Pelo que entendi, deve ser algum problema na parte de busca.