hi , i was having difficulty with the upload_max_filesize , if u set the max file size lesser than the php setting then ur script to report error will only work till this difference between ur max set file size and the php set max size .Hence if the uploaded file exceeds the php max file size then php end abruptly without a trace of error that is it behaves like no file is uploaded and hence no error reported .Sure if uploading a file is optional for a form then a user who uploads larger file will get no error and still the form will be processed only without the file.
The method of using GET can't be used for optional uploads. Can't find help even in the bugs .Be careful with optional uploads.
jahajee