diff --git a/install-dev/upgrade/php/add_default_restrictions_modules_groups.php b/install-dev/upgrade/php/add_default_restrictions_modules_groups.php
index abd1ae996..dd009061c 100644
--- a/install-dev/upgrade/php/add_default_restrictions_modules_groups.php
+++ b/install-dev/upgrade/php/add_default_restrictions_modules_groups.php
@@ -41,7 +41,7 @@ function add_default_restrictions_modules_groups()
 		FROM `'._DB_PREFIX_.'shop`');
 	foreach ($groups as $group)
 	{
-		if (!is_array($modules))
+		if (!is_array($modules) || !is_array($shops))
 			return false;
 		else
 		{
@@ -49,10 +49,10 @@ function add_default_restrictions_modules_groups()
 			foreach ($modules as $mod)
 				foreach ($shops as $s)
 					$sql .= '("'.(int)$mod['id_module'].'", "'.(int)$s.'", "'.(int)$group['id_group'].'"),';
-			// removing last comma to avoid SQL error
-			$sql = substr($sql, 0, strlen($sql) - 1);
-			$res &= Db::getInstance()->execute($sql);
+				// removing last comma to avoid SQL error
+				$sql = substr($sql, 0, strlen($sql) - 1);
+				$res &= Db::getInstance()->execute($sql);
 		}
 	}
 	return $res;
-}
+}
\ No newline at end of file
diff --git a/install-dev/upgrade/php/generate_root_category_for_multishop.php b/install-dev/upgrade/php/generate_root_category_for_multishop.php
index ddf6be28d..851572863 100644
--- a/install-dev/upgrade/php/generate_root_category_for_multishop.php
+++ b/install-dev/upgrade/php/generate_root_category_for_multishop.php
@@ -54,29 +54,35 @@ function generate_root_category_for_multishop()
 	');
 
 	$data = array();
-	foreach ($langs as $lang)
-		foreach ($shops as $shop)
-			$data[] = array(
-				'id_lang' => $lang['id_lang'],
-				'id_shop' => $shop['id_shop'],
-				'id_category' => $id,
-				'name' => 'Root',
-				'link_rewrite' => '',
-			);
-	Db::getInstance()->insert('category_lang', $data);
+	if(is_array($shops) && is_array($langs))
+	{
+		foreach ($langs as $lang)
+			foreach ($shops as $shop)
+				$data[] = array(
+					'id_lang' => $lang['id_lang'],
+					'id_shop' => $shop['id_shop'],
+					'id_category' => $id,
+					'name' => 'Root',
+					'link_rewrite' => '',
+				);
+		Db::getInstance()->insert('category_lang', $data);
+	}
 
 	$categories = Db::getInstance()->executeS('
 		SELECT `id_category`
 		FROM `'._DB_PREFIX_.'category`
 	');
 	$data = array();
-	foreach ($categories as $category)
-		foreach ($shops as $shop)
-			$data[] = array(
-				'id_category' => $category['id_category'],
-				'id_shop' => $shop['id_shop']
-			);
-	Db::getInstance()->insert('category_shop', $data);
+	if(is_array($shops) && is_array($categories))
+	{	
+		foreach ($categories as $category)
+			foreach ($shops as $shop)
+				$data[] = array(
+					'id_category' => $category['id_category'],
+					'id_shop' => $shop['id_shop']
+				);
+		Db::getInstance()->insert('category_shop', $data);
+	}
 
 	Db::getInstance()->execute('
 		UPDATE `'._DB_PREFIX_.'category`
@@ -90,4 +96,4 @@ function generate_root_category_for_multishop()
 	');
 	
 	generate_ntree();
-}
+}
\ No newline at end of file
diff --git a/install-dev/upgrade/php/p15012_add_missing_columns.php b/install-dev/upgrade/php/p15012_add_missing_columns.php
index fcff0b101..8fb9569f9 100644
--- a/install-dev/upgrade/php/p15012_add_missing_columns.php
+++ b/install-dev/upgrade/php/p15012_add_missing_columns.php
@@ -160,22 +160,24 @@ function p15012_add_missing_columns()
 		if (empty($table))
 			continue;
 		$list_fields = $db->executeS('SHOW FIELDS FROM `'._DB_PREFIX_.$table.'`');
-		foreach($list_fields as $k => $field)
-			$list_fields[$k] = $field['Field'];
-		foreach ($cols as $col => $q)
-		{
-			// do only if column exists
-			if (in_array($col, $list_fields))
-				$do = 'mod';
-			else
-				$do = 'add';
-
-			if (!empty($q[$do]))
+		if (is_array($list_fields))
+			foreach($list_fields as $k => $field)
+				$list_fields[$k] = $field['Field'];
+		if (is_array($cols))				
+			foreach ($cols as $col => $q)
 			{
-				if (!$db->execute($q[$do]))
-					$errors[] = '<subquery><query>'.$q[$do].'</query><error>'.$db->getMsgError().'</error></subquery>';
+				// do only if column exists
+				if (is_array($list_fields) && in_array($col, $list_fields))
+					$do = 'mod';
+				else
+					$do = 'add';
+	
+				if (!empty($q[$do]))
+				{
+					if (!$db->execute($q[$do]))
+						$errors[] = '<subquery><query>'.$q[$do].'</query><error>'.$db->getMsgError().'</error></subquery>';
+				}
 			}
-		}
 	}
 
 	if (sizeof($errors) > 0)
@@ -185,5 +187,4 @@ function p15012_add_missing_columns()
 	}
 	else
 		return true;
-}
-
+}
\ No newline at end of file