it should be: script = Flatten[Table[Table[i, {i, blocks[[j]] + 3, blocks[[j + 1]] - 1}], {j, Length[blocks] - 1}]]; you lost the 'Table'

Alternatively, we can focus on the script of "The Revenant Movie" (I got the script from the internet Movie Script Database (IMSDb)). We can use the SmoothHistogram in order to compute the probability density function of names over the movie and visualize when they are playing an important role. For example, we can do that with the four main roles:

SmoothHistogram[{
Legended[First /@ StringPosition[ToLowerCase[scriptString], "glass"],Style["Hugh Glass (Leonardo DiCaprio)", Bold, 14]],
Legended[First /@ StringPosition[ToLowerCase[scriptString], "henry"], Style["Captain Andrew Henry (Domhnall Gleeson)", Bold, 14]],
Legended[First /@ StringPosition[ToLowerCase[scriptString], "fitzgerald"],Style["John Fitzgerald (Tom Hardy)", Bold, 14]],
Legended[First /@ StringPosition[ToLowerCase[scriptString], "bridger"],Style["Jim Bridger (Will Poulter)", Bold, 14]]}, 
AxesLabel -> {Style["number of letters", Bold, 14],Style["probability density function", Bold, 14]},
Filling -> Axis, 
ImageSize -> Large]

See also the probability density function of other groups of words (spoiler alert):

I hope you found this interesting!