Unable to perform assignment because brace indexing is not supported for variables of this type

Hi all I am trying to compute the local significance at each grid point of my data set by using a student's t-test. If I run the loop line by line it seems to work but when I run it as one step I receive the following error message. Unable to perform assignment because brace indexing is not supported for variables of this type. How can I fix this issue when doing this loop?

Thanks in advance

varH{d} = var(P_High{d},0,3,'omitnan'); %this computes variance
varL{d} = var(P_Low{d},0,3,'omitnan');
n1 = 7;
n2 = 6;

for i = 1:141
    for j = 1:71
        sp{d}(i,j) = ((n1*varH{d}(i,j) + n2*varL{d}(i,j))/(n1+n2-2))^0.5;
        t{d}(i,j) = diff{d}(i,j)/(sp{d}(i,j)*(1/n1 + 1/n2)^0.5);
        num{d}(i,j) = ((varH{d}(i,j)/n1)+(varL{d}(i,j)/n2))^2;
        denom{d}(i,j) = (n1-1)^-1 * (varH{d}(i,j)/n1)^2 + (n2-1)^-1 * (varL{d}(i,j)/n2)^2;
        dof{d}(i,j) = num{d}(i,j) / denom{d}(i,j);
        rou_dof{d}(i,j) = round(dof{d}(i,j));               %round off deg of Fre 
        if rou_dof{d}(i,j) > 0                           %actually all positive
            tcrit{d}(i,j) = CritT(0.05,rou_dof{d}(i,j),'two'); %try tstat
        else
            tcrit{d}(i,j) = rou_dof{d}(i,j);
        end
    end
end

[per isakson]

First run

dbstop if error 

in the command window. The run your script. The execution will halt before throwing the error. Examine the values involved.

And see

• Debug a MATLAB Program and Examine Values While Debugging
• TUTORIAL: how to ask a question (on Answers) and get a fast answer

[Walter Roberson]

You do not show the initialization for some of the variables. As outside observers, we can suspect that you might have incompatible values in the workspace. For example, perhaps you had assigned a numeric value to dof .

Also, it can be confusing to name a variable diff and MATLAB can get confused and think that it is a function under some circumstances (especially if you have load with no output variable named.)