PHP Replace function not working with Internet explorer 8 - php

Question

I have a little problem with my website, it is a free classified ads website where people upload photos to their ad, etc.
Problem: my upload script work perfectly with all my computers, but when I check in my Error_Log it show that a lot of people can't upload their picture (it does upload in the temp folder but when I use the rename function to copy it in the ad folder it does not work and say: No such file blah blah blah. So I found someone who has the problem of uploading and realize that internet explorer was the problem.
My version is :
Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)
which seem to work fine and the version he is using is:
Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; WOW64; Trident/4.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.30729; .NET CLR 3.
which does not work.
Is there any reason why my function do work in Internet Explorer 9.0, Firefox, and Chrome but not in IE 8?
EDIT
(This is the code for transfering the files from temp folder of the user to the ad folder:)
mkdir("./users/".$this->Username."/".$Id, 0755);
mkdir("./users/".$this->Username."/".$Id.'/thumbnail', 0755);
$Files_List = explode("#",$_POST['Files_Names']);
for($i = 0;$i < count($Files_List);++$i)
{
if($Files_List[$i] != "")
{
rename('./users/'.$this->Username.'/temp/'.$Files_List[$i], './users/'.
$this->Username.'/'.$Id.'/'.$Files_List[$i]);
rename('./users/'.$this->Username.'/temp/thumbnail/'.$Files_List[$i], './users/'.
$this->Username.'/'.$Id.'/thumbnail/'.$Files_List[$i]);
}
}
$dir = './users/'.$this->Username.'/temp/';
foreach(glob($dir.'*.*') as $v)
unlink($v);
$dir = './users/'.$this->Username.'/temp/thumbnail/';
foreach(glob($dir.'*.*') as $v)
unlink($v);
echo '<script>window.location = "./message.php?Message=Publier";</script>';
exit(0);
Error message:
[17-Oct-2011 12:31:17] PHP Warning: rename>(./users/francois/temp/thumbnail/2590cd9217.jpg ,./users/francois/186/thumbnail/2590cd9217.jpg ) [href='function.rename'>function.rename]: No such file or directory>in /home/kesimard/public_html/Montreal/publier.php on line 70
Line 70 = rename('./users/'.$this->Username.'/temp/thumbnail/'.$Files_List[$i], './users/'. $this->Username.'/'.$Id.'/thumbnail/'.$Files_List[$i]);

Answer 1

Sounds more like a filesystem issue than a browser issue. Before the rename() functions, try adding this:
if (!file_exists('./users/' . $this->Username . '/' . $Id)) {
mkdir('./users/' . $this->Username . '/' . $Id);
}
if (!file_exists('./users/' . $this->Username . '/' . $Id . '/thumbnail')) {
mkdir('./users/' . $this->Username . '/' . $Id . '/thumbnail');
}