近來項目需要學習起flex，利用FileReference進行上傳文件的試驗。結果總是報告#2038錯誤。
查了很長時間，總算在這找到了不少的提示
IO Error #2038
http://swfupload.org/forum/generaldiscussion/92
其中一段是這樣說的
Flash IO Errors are not very helpful. The same couple of error numbers are returned for just about everything.
Here are some common issues that cause these error codes:
- Invalid URL
- Server max post size or max upload size exceeded
- Server unexpectedly terminates the connection
- Zero byte file uploaded
- Basic Authentication failed
To debug these issues I first verify that my upload is working using a standard HTML upload form pointing at my upload.php
說Flash的IO錯誤提示不是非常有用。幾個錯誤碼就包含所有的錯誤信息。跟著列了IO錯誤通常包含的錯誤，并建議我們先用html原上傳方式確保上傳的頁面沒有錯誤。
結果真是我的up.aspx有錯誤引起的。