diff --git a/src/pocketmine/PocketMine.php b/src/pocketmine/PocketMine.php
index 8510fcb48..82063ae98 100644
--- a/src/pocketmine/PocketMine.php
+++ b/src/pocketmine/PocketMine.php
@@ -144,12 +144,12 @@ namespace pocketmine {
 		}
 	});
 
-	ini_set("allow_url_fopen", 1);
-	ini_set("display_errors", 1);
-	ini_set("display_startup_errors", 1);
+	ini_set("allow_url_fopen", '1');
+	ini_set("display_errors", '1');
+	ini_set("display_startup_errors", '1');
 	ini_set("default_charset", "utf-8");
 
-	ini_set("memory_limit", -1);
+	ini_set("memory_limit", '-1');
 	define('pocketmine\START_TIME', microtime(true));
 
 	$opts = getopt("", ["data:", "plugins:", "no-wizard", "enable-profiler"]);
diff --git a/src/pocketmine/scheduler/AsyncWorker.php b/src/pocketmine/scheduler/AsyncWorker.php
index b02868ad0..e6e2c2037 100644
--- a/src/pocketmine/scheduler/AsyncWorker.php
+++ b/src/pocketmine/scheduler/AsyncWorker.php
@@ -38,7 +38,7 @@ class AsyncWorker extends Worker{
 	public function run(){
 		$this->registerClassLoader();
 		gc_enable();
-		ini_set("memory_limit", -1);
+		ini_set("memory_limit", '-1');
 
 		global $store;
 		$store = [];