[SOLVED] Help with PlayerPrefs.SetInt

I have a script which regenerates one life every 30 minute and then i can subtract one life by clicking a button that activates a “Subtractlife” function. The subtract function bit looks like this

static var maxLives = 5;

static var lives = 5;

static var RegenInterval = 1800; // 30min * 60
static var nextLife = 0;

static function SubtractLife(){
    if(lives <= 0) 
        return false;  
    if (lives == maxLives)  

        nextLife = UnixTimestamp() + RegenInterval;
    PlayerPrefs.SetInt("nextLife", nextLife);
    PlayerPrefs.SetInt("lives", lives);
    return true;

Now my problem is, that when i play my game in Unity, it works but when i play it on my phone it doesnt function properly. I think it is because i get this error “TrySetInt can only be called from the main thread.
Constructors and field initializers will be executed from the loading thread when loading a scene.
Don’t use this function in the constructor or field initializers, instead move initialization code to the Awake or Start function.” But when i do as the error says and put the PlayerPrefs.SetInt to the start function, the error stops showing but the script doesnt function properly in the game. Am i doing something wrong?

I think you’re missing PlayerPrefs.Save().