cd('E:/image_trans/Emis32_%d.bin');
This does not look like a valid folder name. Is there really a % character? Later on this is used as a file name.
Whenever you open a file, check for the success:
[e, msg] = fopen(f);
assert(e > 0, msg); % Show the message, if fopen failed
You create the file handle called "e" with fopen, but try to close "f" with fclose.
I guess, this cleaned version is working:
Folder = 'E:/image_trans/';
fntest = dir(fullfile(Folder, '*.raw'));
rows = 442;
cols = 503;
data = zeros(numel(fntest), rows * cols); % pre-allocate for speed
for i = 1:numel(fntest)
file = fullfile(Folder, fntest(i).name);
[fid, msg] = fopen(file, 'r');
assert(fid > 0, msg);
data(i, :) = fread(fid, [1, rows*cols], 'uint16');
fclose(fid);
end