could somebody help me? what should I do?

??? Undefined function or variable “i_stat_0”.

Error in ==> get_variance_of_endogenous_variables at 63

vx1(i_stat,i_stat) = ghx(:,i_stat_0)*vx(i_stat_0,i_stat_0) ghx(:,i_stat_0)’+ghuSigma_e*ghu’;

Error in ==> osr_obj at 54

vx = get_variance_of_endogenous_variables(dr,i_var);

Error in ==> csminwel at 65

[f0,cost_flag] = feval(fcn,x0,varargin{:});

Error in ==> osr1 at 98

[f,p]=csminwel(‘osr_obj’,t0,H0,],crit,nit,options_.gradient_method,i_params,…

Error in ==> osr at 47

osr1(i_params,i_var,W);

Error in ==> toke at 291

osr(var_list_,osr_params_,obj_var_,optim_weights_);

Error in ==> dynare at 132

evalin(‘base’,fname) ;

I wrote mod file:

optim_weights;

pi 1;

y 1;

end;

osr_params phi_pi phi_y;

phi_pi=1.5;

phi_y=0.5;

osr;