Shocks on exogenous variables

Hi all, I want to add the exogenous shocks on my model, but it can’t work . And I don’t know how to solve it. My approach is to add

var a; stderr 0.009;
var s; stderr 0.009;
var a, s = 0.009*0.009;


to my steady state model.
How can I debug this question?

this is my workable file
chu0210_ss.mod (1.9 KB)

and this is the error one
chu0217.mod (1.8 KB)

What is the error message you are getting and which Dynare version are you using?

here is the error message :
??? Error using ==> print_info at 42
Blanchard Kahn conditions are not satisfied: no stable equilibrium

Error in ==> stoch_simul at 100
print_info(info, options_.noprint, options_);

Error in ==> chu0217 at 273
info = stoch_simul(var_list_);

Error in ==> dynare at 235
evalin(‘base’,fname) ;

and my dynare version is 4.5.7 thanks

Check your timing. For example, why is p predetermined in your model?