I think this is related to the fix to bug #13094. Here is an example:

uptest1.php:
<form action="uptest2.php" method="post" enctype="multipart/form-data">
  <input type="file" name="myfile">
  <input type="submit">
</form>

uptest2.php:
<?
  var_dump($HTTP_POST_FILES);
?>

When I use PHP 4.0.8, this works as expected. It uploads to a temporary file, calls uptest2.php (giving all correct information) and deletes the temporary file.

In PHP 4.2.0, it uploads the file (it shows up in my temp dir), but then I get a CGI timeout. It appears as though uptest2.php is never called. The temporary file is not deleted.

I would gladly downgrade to 4.0.8, but I need some of the newest COM functionality. If there is a way to get a snapshot version from between about the 20th and 26th of october, that would be a good temporary solution (for me anyway), but a fix would be better (assuming this is actually a bug).