Hello Mike
The PHP.ini is correct: file_uploads is set to "on" (it's displayed as "1" in phpinfo.php)
I still don't understand why uploading is impossible on my redhat server.
Here is the PHP code that works fine on Win98 and FreeBSD:
<?php
if($test_file != ""

{
$file_ext = str_replace(".", "", strstr($test_file, '.'));
$updir = "../my_pics/";
$file_name = "my_test_file." . $file_ext;
@copy("$test_file", "$updir/$file_name"

or die ("Couldn't upload the file."

;
return;
} else {
}
?>
<form name="test_form" method="POST" action="test.php">
<input type="file" name="test_file">
<input type="submit" value=" UPLOAD ">
</form>
Thanks for your time !