ORA-00905:oráculo de error de palabra clave faltante

El problema más probable es MJNSXJJRW AS S0 . Usas el AS palabra clave al definir alias de columna, no al definir alias de tabla.

CREATE VIEW MJNSXJJRW_view AS  
SELECT B.oID AS "_oid", B.oTm AS "_otm" 
FROM 
(SELECT DISTINCT oID, oTm FROM MJNSXJJRW) B 
LEFT JOIN MJNSXJJRW S0 ON 
    B.oID = S0.oID AND 
    S0.idx = 0 AND 
    S0.kID = "str_val" ; 

Supongo que "str_val" es una columna, no un literal de cadena. Si es lo último, debe usar comillas simples.