Upload file does not work correctly

[flovntp]

I just try to upload a new file for a brightCove Video and, at the end of the upload, when publishing the object, eZ return an error :

The requested object is not available.
Possible reasons:
The ID number of the object is incorrect. Check the URL for spelling mistakes.
The object is no longer available.

Seems that the object was not created and eZ try to get back to the edit interface.
I use Kaliop demo website for BrightCove.

I try to upload a video of 4Mo, type mp4

Thanks

Florent