parallel computing problem in subfuction

I have this simple parfor code

     Ne = round((E0max - E0min)/dE0);
     parfor count =1:Ne
         [etap, etaNzrp(count)] = shooting(E0min+(count-1)*dE0);
     end

when I run in for loop, it looks just fine. But this parfor loop report an error in subfunc shooting.

    function [eta, etaNz] = shooting(E)
    % Shooting method

    global m Eref Unef Egw bwbwbwb Egb dz Angstrom Nz hbar U e

    % Conduction band nonparabolicity
    mn = m .* ((1 + (E - Eref - Unef) / Egw) .* (bwbwbwb == 0) + (1 + (E - Eref - Unef) / Egb) .* (bwbwbwb == 1));

    if (min(mn) <= 0)
        disp('Error! Mass is negative!')
        return
    end

    eta = zeros(1, Nz);
    eta(2) = eps * dz * Angstrom;
...
...

the error appear in 'eta(2) = eps * dz * Angstrom;'

In an assignment A(I) = B, the number of elements in B and I must be the same.

How to fix it?