It seem to be I have a problem on that code as this only go though the first one and then stopped...so other file extension is not allow...
//Check the file extension
if (($_FILES["file"]["type"] == "application/pdf")
|| ($_FILES["file"]["type"] == "application/doc")
|| ($_FILES["file"]["type"] == "application/docx")
|| ($_FILES["file"]["type"] == "application/ppt")
|| ($_FILES["file"]["type"] == "application/pptx")
&& ($_FILES["file"]["size"] < 20000000))
{