I can't delete the files sent by BOTs

[x1pepe]

I can't delete the files sent by BOTs.
Part of the code ...

// DELETE FILE
if (msg.isFile) {
// If msg its a file ...
bot.sendMessage("The file will be delete in 2 seg.");
delay (2000);
bot.deleteMessage(msg.ID, msg.chatID);
bot.deleteMessage(bot.lastBotMsg());

... Thaks.