Why does for loop not show me the two plots?

%Loading data
for ii=1:2
load(['uz' num2str(ii) '.txt']);
end
B=cat(2,uz1,uz2);
step=100;
%Plotting data
for k=1:2
subplot(1,2,k)
[X,Y]=meshgrid([min(B(:,1,k)):step:max(B(:,1,k))],[min(B(:,2,k)):step:max(B(:,2,k))]);
[Z]=griddata(B(:,1,k),B(:,2,k),B(:,4,k)*10e4,X,Y);
surf(X,Y,Z,'EdgeColor','none');
shading interp
axis equal
view(0, 90)
colorbar
end

This is the errors:

Index exceeds matrix dimensions.

[Walter Roberson]

Which line does it give the error on?

What does size(B) show?