Conversion to struct from double is not possible

I am trying to load different dicom images in a stack and get this error ''Conversion to struct from double is not possible''

clc;
clear all;
close all;

N=5;
img_dir ='D:\Stelios PhD files'

strfile = 'Z01';
img = dicomread(fullfile(img_dir, strfile));
siz_img = size(img);

dicomlist = dir(fullfile(pwd,img_dir,'*.dcm')); 

I=0;

for cnt = 1 : numel(dicomlist) 
I{cnt} = dicomread(fullfile(pwd,img_dir,dicomlist(cnt).name)); 
end 

% create result matrix:
D = NaN([dicomlist N]);
D(:,:,1) = I;   

D=squeeze(D);

Ds=smooth3(D);

imagesc(Ds(:,:,N));
imagesc(squeeze(Ds(:,N,:))');
imagesc(squeeze(Ds(N,:,:)));

%# view slices as countours
contourslice(Ds,[],[],1:size(Ds,3))
view(3), axis tight
daspect([1 5 1])

ANy help???

[KSSV]

You have not specified the error line....

[Stelios Fanourakis]

sorry. That line.

dicomlist = dir(fullfile(pwd,img_dir,'*.dcm'));

[Stephen23]

@Stelios Fanourakis: please show us the entire error message. This means all of the red text.

[KL]

using pwd,img_dir together is also strange. your img_dir is like 'D:\...' and pwd would give you your current working directory path. Something like,

 'C:\Users\D:\Stelios PhD files'