Error in Ada language (raised TASKING_ERROR: s-tasren.adb: 446)

I am programming a task in Ada and when executing I get this error. Does anyone know what this error means?

  

raised TASKING_ERROR: s-tasren.adb: 446

The code is this:

with pkg_procedure;use pkg_procedure;
with Ada.Integer_Text_IO;use Ada.Integer_Text_IO;
with pkg_tarea;use pkg_tarea;

procedure main is
num:Integer;
t1:tarea_t;

begin
   loop
      t1.EstadoConsultas;
      Leer_entero(num);
      put("numero introducido");
   end loop;  

end main;