I discovered that my upload form seems to work in all common browsers, including Firefox, Chrome and IE8.

But when it comes to IE9 it fails.

Btw, the form is in a PHP file.

This is what the file looked like:

```
<? 
require_once ($_SERVER["DOCUMENT_ROOT"].'/_meta/phpFunctionsLibrary.php');
echo '--- HTML Code including the form element ---'
?>

```

Then I deleted the "require\_once" line, and suddenly it worked in IE9 also.

Fortunately, in this case the Library is dispensable to a certain extent, but of course I can't rely on that.

So I need to know what could have caused this mess in IE9...