请问这个错误怎么解决？

Magicloud

%createlang plpgsql drupal
createlang: language installation failed: ERROR:  could not find function "plpgsql_validator" in file "/usr/local/pgsql/lib/plpgsql.so"

PostgreSQL 7.5.2004.06.25

如果确实不能解决（是测试本身的问题）的话，那下边的两个函数如何改写为c或sql？
CREATE FUNCTION "greatest"(integer, integer) RETURNS integer AS '
BEGIN
  IF $1 >; $2 THEN
    RETURN $1;
  END IF;
  RETURN $2;
END;
' LANGUAGE 'plpgsql';

CREATE FUNCTION "rand"() RETURNS float AS '
BEGIN
  RETURN random();
END;
' LANGUAGE 'plpgsql'

谢谢