Serbianu - the error message is telling you that the function func1 must return a column vector. From your code, the vector xd is a row vector. So just change this to a column vector as
function xd = func1( t,x )
xd = zeros(3,1);
xd(1)=2*x(1)+3*x(2)-4*x(3);
xd(2)=-x(1)+2*x(2);
xd(3)=(-2)*x(1)+x(2)+2;
end
In the above, we've added a line that just initialized xd as a column vector with three elements. Try making the change and see what happens!
(An alternative solution would be just to transpose the vector xd.)
