Only instructions I've found thus far are on the PHP site and searching google. However, it looks like a common problem is not having the upload_tmp_dir set to writeable by the webserver. Without that, it won't be able to write out the file. Oh, and I did ask you to check and make sure that you are not running in safe_mode correct?
As for the allowed_files problem, I'll take a look at that and see what's going on.
-------------------
Rick Baker
UBBThreads developer
