Try part of C# not being Read

I'm not very good at code so perhaps someone can point me in the right direction as to why this part of the code is not being reached. If I comment all of the update out above it then it does read. So I'm sure I'm buggering up something not being too familiar with it.

 try
         {
             MoveObject(sp.ReadByte());
             print(sp.ReadByte());
         }
         catch (System.Exception) {
 
         }

This is the code with the rest of the Update.

     // Update is called once per frame
     void Update () {
         amountToMove = speed * Time.deltaTime; // New Test For Arduino Move Cube
             //print("BytesToRead" +sp.BytesToRead);
             message2 = sp.ReadLine();
             
         string message = sp.ReadLine(); //get the message...
         if(message == "") return; //if its empty stop right here
         // parse the input to a float and normalize it (range 0..1) (we could do this already in the Arduino)
 
         float input =  1 -  float.Parse (message) / 100f;
         // set the slider to the value
         float oldValue = slider.value; // -------- this is new
         slider.value = input;
 
         // after the slider is updated, we can check for the other things for example play sounds:
 
         if (source.isPlaying) return; // if we are playing a sound stop here
 
         // else check if we need to play a sound and do it
         if (slider.value > 0.9f && oldValue <= 0.9f) // ---------this has changed
             source.PlayOneShot (BrightnessAudioClips [Random.Range (0, BrightnessAudioClips.Length)]);
 
         else if (slider.value < 0.15f && oldValue >= 0.15f) //----------this has changed
             source.PlayOneShot (DarknessAudioClips [Random.Range (0, DarknessAudioClips.Length)]);
         
         try
         {
             MoveObject(sp.ReadByte());
             print(sp.ReadByte());
         }
         catch (System.Exception) {
 
         }
     }