what is the error 'Index exceeds matrix dimensions.'

after coding this

clear

clc

n=0

throat_volume=zeros(15625,1)

for k=1:25:601

for j=1:25:601

for i=1:25:601

n=n+1

basefilename=sprintf('Ax_%d_%d_%d_link2.dat',k,j,i)

fullfilename=fullfile(basefilename);

fileID=fopen(fullfilename,'r+')

% fseek(fileID,7,'bof');

sizeA=[8 Inf]

A=fscanf(fileID,'%f',sizeA);

fclose(fileID)

A=A';

throat_volume(n)=mean(A(:,7))

end

end

end

i get this error 'Index exceeds matrix dimensions.'

what is the matter of this code?

please help me.