Cannot upload files nor create folders

Hi,

I'm encountering an issue uploading files from both desktop and mobile (iPad/iPhone).
We cannot upload a file except in the personal workspace. Otherwise we get the following message:
"
A folder/file named 'Web' could not be added because of an unknown error.
"

We tried to upload in the Home and in the Netfolders on which the user has the "full control" (NTFS rights on each share).

The upload limit has not been modified and is set to 50MB.. we are trying to upload small files (200KB).

I would appreciate your help.

Thanks a lot!