Error during creation of a VideoReader Object

Hello, I am trying to exctract all frames of a video (.avi) created in another matlab script. Below the code:

if true
  %Acquisisco il percorso del FieldMovie.avi
folder = fileparts(which('FieldMovie.avi'));
movieFullFileName = fullfile(folder,'FieldMovie.avi');
%Creazione dell'oggetto 'videoObject'
videoObject = VideoReader(movieFullFileName);
%Creazione di un output folder per i frames
[folder,MovieName,extention] = fileparts(movieFullFileName);
folder = pwd;
outputFrame = sprintf('%s/Movie Frames from %s', folder,MovieName);
for frame = 1 : 129
%Estrazione dei frame dal video
thisFrame = read(videoObject, frame); % legge soltanto il frame specificato  da l'indice 'frame'
%Scrittura dell' Array Immagine nell' output file costruito di seguito
outputBaseFileName = sprintf('Frame %4.4d.png', frame);
ExtractFrame = fullfile(outputFrame, outputBaseFileName);
end
end

The error returned is: Error in outputFolder (line 12) videoObject = VideoReader(movieFullFileName);

Someone might help me to understand what does it means? Thanks in advance

[Guillaume]

Please give the full text of the error message, everything in red.

Note that I don't really understand the point of deconstructing the path returned by which to rebuild it the same on the next line (and deconstruct it again several lines later to then discard that deconstruction). However, it should be unrelated to your error.

[Davide Magnelli]

Here the full error message:

Error using VideoReader/init (line 607) The filename specified was not found in the MATLAB path.

Error in VideoReader (line 172) obj.init(fileName);

Error in outputFolder (line 12) videoObject = VideoReader(movieFullFileName);

[Walter Roberson]

It appears that you do not have a file named FieldMovie.avi anywhere on your MATLAB path.