Problem with forecast command

Please, i really help to forecast some variables. I followed the instructions of Dynare guide on the syntax of the forecast command but i got the following error message:

Undefined function or variable “ex”.
Error in dyn_forecast (line 116)
[yf,int_width] = simultxdet(y0,ex,oo_.exo_det_simul,…
Error in myfiscal (line 292)
info = dyn_forecast(var_list_,‘simul’);
Error in dynare (line 180)
evalin(‘base’,fname) ;
myfiscal.mod (2.65 KB)

That is a bug. A workaround is specifying

[quote=“jpfeifer”]That is a bug. A workaround is specifying

I tried the given workaround, but it didn’t work. I 'm very confused.

What happens when you set periods to 10?