You are mixing up Scriptlet variables with EL variables.
These things are not the same.
${movieCollection} does not refer to your scriptlet variable movieCollection, but is rather looking for an attribute of that name.
ie the
java equivalent of ${movieCollection} would be pageContext.findAttribute("movieCollection");
One solution (for this example page)
add this to the end of your <% scriptlet %> section where you define the list of movies:
This puts the movieCollection variable into the page attribute space where your EL reference can then find it.