PlayerPrefsException on Windows

I have a Unity3d game build on Windows width the 5.3.4 version. I get this error

 PlayerPrefsException: Could not store preference value at UnityEngine.PlayerPrefs.SetString (System.String key, System.String value) [0x00000] in :0 at SlotManager+c__Iterator3.MoveNext () [0x00000] in :0 (Filename: Line: -1)

Im doing is just a regular PlayerPrefs.SetString. According to documentation (http://docs.unity3d.com/ScriptReference/PlayerPrefsException.html) this exception shouldn't appear on Windows platform and I couldn't find any information about this subject. Anyone with the same problem?

This is the code causing problem:

 if (wonBonus)
         {
             symbolsGrid.GetComponent<SymbolsGrid>().AnimateBonus();
             symbolsGrid.GetComponent<SymbolsGrid>().SaveState();
             PlayerPrefsX.SetStringArray("bonusPrizes", curSpin.bonusprizes);
             string thisSpinStr = JsonConvert.SerializeObject(thisSpin);
             PlayerPrefs.SetString("thisSpin", thisSpinStr);
             PlayerPrefs.SetFloat("curBet", (float)(curBet));
             PlayerPrefs.SetInt("bettedLines", bettedLines);
             PlayerPrefs.SetInt("betIndex", betIndex);
             PlayerPrefs.SetFloat("totalPayment", totalPayment);
             PlayerPrefs.SetFloat("wonOnFreeSpin", wonOnFreeSpin);
             PlayerPrefs.SetFloat("bonusWin", (float)bonusWin);
             PlayerPrefs.SetInt("freespins", freespins);
             PlayerPrefs.SetInt("delayedFreeSpinWin", delayedFreeSpinWin);
             PlayerPrefsX.SetBool("endFreespins", endFreespins);
 
             string freespinsSpinsStr = JsonConvert.SerializeObject(freespinsSpins);
             PlayerPrefs.SetString("freespinsSpins", freespinsSpinsStr);
             if (isFreeSpinning) falls.GetComponent<Falls>().IsDay(true);
             yield return new WaitForSeconds(2.5f);
             PlayerPrefs.SetFloat("balance", balance);
             StartBonusAnimation(true);
         }