Assignment has more non-singleton rhs dimensions than non-singleton subscripts

I am getting an error message in my code "Assignment has more non-singleton rhs dimensions than non-singleton subscripts". The systax of code is given here.First i have tried to solve it by using similar types of questions in mathworkscentral. Unfortunately i am unable to resolve it. The size of each variable is

1. size(a) is 1x100
2. size(b) is 1x100
3. size(c) is 1x100
4. size(p) is 1x100
5. size(q) is 1x1
6. size(res) is 1x1
7. size(E) is 1x1
8. res is a structure please anyone help me to resolve this issue..regardsDebashis

 for i=1:length(q)
     for j=1:length(p)
     [a(i,j) b(i,j) c(i,j)]=p_call(p(j),q(i),res,E)
 end
end

[Rik]

There is no obvious reason why this should fail, even if I would choose to separate outputs with a comma as well as a space. What are the contents of p_call? Are all outputs scalars?