Index out of range why? (possible bug)

Ingame the script will not run as the index is out of range on this script. It is only occurring on one line.

 public class AIController : MonoBehaviour {
         float tlu;
         float tld;
         int RibI;
         public float[] tibl;
         int RprsdI;
         public float[] tprsdl;
         public int whichOne = 0;
     
         public bool record;
     
         void Update () {
             float timer = 0;
             bool pressing = false;
     
             if (record) {
                 tlu += Time.deltaTime;
                 if (Input.GetKeyDown ("right")) {
                     tibl [RibI] = tlu;
                     RibI++;
                 }
                 if (Input.GetKey ("right")) {
                     tld += Time.deltaTime;
                 }
                 if (Input.GetKeyUp ("right")) {
                     tprsdl [RprsdI] = tld;
                     RprsdI++;
                     tld = 0;
                     tlu = 0;
                 }
             }
             if (!record) {
                 
                 timer += Time.deltaTime;
     
                 //this line
                 if (timer >= tibl[0]) {
                     transform.Translate (1, 0, 0);
                     timer = 0;
                     pressing = true;
                 }
                 if(timer >= tprsdl[whichOne] && pressing) {
                 
                     whichOne++;
                     pressing = false;
                     timer = 0;
                 }
             }
         }
     }

I honestly don't know how, I think it is something that i did. It occurs on that line and only that line, and yes i did set the values of the array to a number higher than zero and it still did not work. I appreciate the help.