Error in the code?

Hey, I made a code and it wont compute, can you tell me what is wrong with it?

%%%%

var x pi i u Ex Epi ;

varexo epsilon;

parameters beta kappa gamma rhou phipi ;

%—2. Calibration—
beta=0.99;
kappa=0.13;
sigma=1;
rhou=0.9;
phipi=1.5;

%----3. Model----------

model(linear);
Ex = x(+1);
Epi = pi(+1);
x = Ex - (1/gamma)(i - Epi)+u;
pi = beta
Epi + kappax;
i = phipi
pi;
u = rhou*u(-1) + epsilon;

end;
%% No need to include initial starting values if you are simulating a log-linearized model%%

shocks;
var epsilon;
stderr 1;
end;

steady;
stoch_simul;

As Dynare says:

Please set gamma.