name of subquery not accessible by where clause
Simiply use an Inner Join (your current query using a Scalar Subquery is similar to an Outer Join):

SELECT
  MOVIE.NAME,
  COUNT(*) AS RENTCOUNT
FROM MOVIE 
JOIN MOVIERENTED 
ON MOVIERENTED.MOVIEID=MOVIE.MOVIEID
GROUP BY MOVIE.NAME, MOVIE.MOVIEID
ORDER BY RENTCOUNT;