这段上传的代码我实在是找不出来那里错了

<?php
if($_POST['doupload']!=""){
if($_FILES['upfile']['size']==0){
echo "请选择需要上传的图片";
echo $_FILES['userfile']['error'];
exit;
}else{
$imageinfo=getimagesize($_FILES['upfile']['tmp_name']);
if($imageinfo[0] > 120 or $imageinfo[1] > 80){
echo "图片大小不符合标准";
exit;
}elseif($imageinfo[2] < 1 or $imageinfo[2] > 3){
echo "简介图片只能是GIF,JPG,PNG格式";
exit;
}
if($imageinfo[2] == 1){
$imageinfo[2] = ".gif";
}elseif($imageinfo[2] == 2){
$imageinfo[2] = ".jpg";
}else{
$imageinfo[2] = ".png";
}
$imgname=date(YmdHis).substr(md5($_FILES['upfile']['name']),0,5).$imageinfo[2];
$category="C:\Apache2\htdocs\upload".'$imgname';
if(copy($_FILES['upfile']['tmp_name'],$category)){
unlink($_FILES['upfile']['tmp_name']);
echo "上传".$_FILES['upfile']['name']."文件成功";
}
}
}
?>
没有什么显示,也没有文件上传,应该是copy()这里出错了,我echo $imgname没有值,这是怎么回事??