I have a flex app doing multiple file upload, and keep getting this error: Error #2038: File I/O Error
Flex gives this error, yet it seems to work because the upload does get processed. This was happening intermittently, now on every attempt. Any ideas on what might be going on here? I've checked that permissions are read/write, google'd something about a trailing slash issue with the url. I'm at a loss as to what could be going on.
Are you using an SSL certificate on the server you're uploading to? I've had issues in the past where the Flash Player will randomly fail due to an invalid SSL certificate...
Cheers
It might be a good idea to look at the trafic using a tool like charles. That might give you a better indication of what really goes wrong.
It's also good to know that the Flash player with uploads forgets to send some cookies, this can cause your session at the server to be different.
It could also be that the url to connect to the server isn't correct. Check to see if it is a relative URL, and if so, fully qualify it. I have found this bahavior myself...and the code can work in IE but not in other browsers, not on the Mac, not on Mobile.
I was also having the same problem during file upload some 3-4 months before. The call was going to servlet but in the front end i was getting some error (#2038).
Later i found out that my code was having some exception in Servlet and then it was not getting processed correctly. I does not remember what the exception was, but when i solved that exception, the error was gone.
b/w are you using commons-file-upload to upload the file?
Regards, Anoop
There is a limit to concurrent connections that are supported. I think its 3 or 5, not sure. Are you getting the error when you attempt to upload more than 3 files?
来源：https://stackoverflow.com/questions/1545715/flex-error-2038-file-i-o-error