Cannot CAST '33.33' to INT
Try this 

    SELECT AVG(cast(cast([varcharColumn] as decimal) as int))
      FROM View 
     WHERE isnumeric([varcharColumn]) = 1 
     AND cast(cast([varcharColumn] as decimal) as int) &gt; 0
     AND CreatedDate &gt; @StartDate AND CreatedDate &lt; @EndDate