Image Upload issue on 4.4.2

Hi all
I just completed a fresh installation on my server provider (servage.net) for this domain https://www.cooki.it/

After installation I tried to upload some images and I incurred in this issue :
all files uploaded are 0 byte size and so every file is unreadable.

I checked folders permissions and those are ok (I set them 755 but nothing changed).
I checked .htaccess file and it seems ok.
I tried to switch theme to each one installed by default, nothing changed.

My installation is in a shared hosting and php running for the specific domain (cooki.it) is php 5.4. ( I can switch to 5.3 or 5.2. but not to php 5.5.).

As i said, the installation is fresh : no plugins, only default stuff, so I don’t think is something tied to plugins or added components.

Any ideas?
thanks in advance for any hints and support. ??