I'm having a problem too. I looked at the bomb tutorial, Code:

---

//BOMB

action timer
{
     my.skin = 2;
     my._DAMAGE = 200; // set different damage values for different timers
     my.enable_click = on;
     my.event = start_timer;
} 

function start_timer()
{
     wait (1);
     second_counter = 10; // explodes after 10 seconds
     while (my != null)
     {
          second_counter -= 1;
          my.skin = 2;
          
          waitt (14);
          my.skin = 1;
          waitt (2);
          if (second_counter < 1)
          {
               range = my._DAMAGE * 2;
               damage = my._DAMAGE;
               temp.pan = 360;
               temp.tilt = 180;
               temp.z = range;
               indicator = _EXPLODE; // not a friendly scan
               scan_entity (my.x, temp);
               morph (explo_sprite, me);
               my.oriented = on;
               my.pan = 0;
               while (my.frame < 7)
               {
                    my.frame += 3 * time;
                    wait (1);
               }
               actor_explode(); // remove the explosion sprite
          }
     }
} 

---

saved it in template_6/codes, added the script to my level, attached the timer action to something, and errors such as
parameter _DAMAGE not found
parameter secondtimer not found and etc
please help? hopefully a step-by-step guide would be useful