I want to have an online high score system for my game so i tried to use the example of the WWWform script reference.
But when I launch the game and try to send some data, I have this error i don't understand :
Error downloading: necessary data rewind wasn't possible
Cam someone explain what it mean and how to solve the problem?
Wow, never seen that error before. I have no idea what it means.
Where do you see the error, is it a unity runtime error in the console, or is it in the result from your webserver?
Either way, you might want to look at this answer which lays out exactly how to send and receive data using www to a server, however it may not help if the error is coming from your web server.
How can I send and receive data to and from a URL, i.e. server side scripts, web services, etc?
This page:
http://bugs.php.net/bug.php?id=47204&edit=1
describes something similar as a bug against the PHP version of Curl. It suggests that the problem is caused when using Digest authentication or following a server side re-direct. I suspect whatever is causing problems for PHP also causes problems for the WWWPost class. Guess Unity uses Curl also, but not on the iPhone. Note I am not saying that you have a PHP problem!
If you have any PHP coders there, perhaps hit your high score site using a PHP page and see if you get the same problem. I don't have a solution for you, but can only suggest you try without authentication to see if that is related.
I just finished an Unity3D Score System which provides online score service.
Please download and try. Suggestion is welcome.
See my post at the following url. It may help.
http://forum.unity3d.com/threads/83904-WWW-error-necessary-data-rewind-wasn-t-possible-SOLVED