Unknown exception 0x80000026 Error/Crash with Simulink

Hello, I have created a system object inside a simulink model. Right now it does something like this (nothing so far:P, because I'm stuck on technicalities):

 function setupImpl(obj,u)
            % Implement tasks that need to be performed only once, 
            % such as pre-computed constants.
            obj.memory = -ones(11, 11);
 end
 function [Out] = stepImpl(obj,message)
            % Implement algorithm. Calculate y as a function of
            % input u and discrete states.
            i = find(obj.memory(:,1) == message(1));

            if(all(i ~= 0)) %find id already in memory
                Out = i(1);
            else 
                Out = i(1);
            end
 end

When it executes it crashes with this error message: Unknown exception 0x80000026 I realized that I have to use the scalar value of i, but when I call it i(1) it won't work. Also i is always supposed to either be empty or return 1 index (there cannot be more than 1 occurrence).

Any ideas?

[highWaters]

I made this modification:

function [Out] = stepImpl(obj,message)
            i = find(obj.memory(:,1) == message(1),1);
            if(isempty(i) ~= 0) 
                Out = i(1);
            else 
                Out = i(1);
            end
 end

But still when I try to access i(1) the crash persists.

Answer 1

[Walter Roberson]

            if isempty(i)
                Out = [];
            else 
                Out = i(1);
            end

[highWaters]

Thank you!