[Eeglablist] pop_export to txt error

[Angelika Wolman]

Hello all,

I want to export my EEG files to a .txt file. For this, I use the following code:

for i = 1:length(files)
filename = files(i).name;

    EEG = pop_loadset( 'filename', filename, 'filepath', directory_name);

    EEG = eeg_checkset( EEG );

    EEG = pop_export(EEG,'filename',[filename(1:end-4),'.txt'],'transpose','on','separator',',','precision',7,[directory_name '/_7_task_text']);

end

But I get the following error:

Error using cell/unique (line 85)
Cell array input must be a cell array of character vectors.

Error in unique_bc (line 47)
    [C,IA,IB] = unique(A,varargin{:},'legacy');

Error in finputcheck>removedup (line 248)
    [tmp indices] = unique_bc(cella(1:2:end));

Error in finputcheck (line 115)
                vararg = removedup(vararg, verbose);

Error in pop_export (line 122)
g = finputcheck(options, { ...

Do you know why I get this error and what I can do?
Thank you very much!!
Angelika