Put it outside the directory where Elgg has been installed and see what happens.

Is it on your own server? Maybe you need to check Apache settings (openbasedir?) as php might not be allowed to write to the data directory regardless of permission settings.

In case of a webserver you might need to ask your support.

Thanks, Shouvik and iionly, I was on vacations. I will try your suggestions and give you guys feddback.

Hi guys, thank you for the support.

I talked to the support of the web server and they allowed uploads (permission 777), but it doesn't worked.

I tryed too move the data folder to the root of the site and the message was the same.

May I be doing something too basic, like missing the right path of the folders or something like?

Thank you guys! It was it. I'd missed the correct full path of the files.

Thank you for your support