I'm using the NextGen Public Uploader plugin, and it works fine on the local server when i try to upload a image, after i uploaded it on a server, it won't work, gives me the next error:
Unable to write to directory /home/vioo6154/public_html/\wp-content\gallery\galerie-retro. Is this directory writable by the server?
thank you very much.
There are two different things that could prevent your upload from working.
Permissions - as it states the permission may state the directory you are trying to upload to is not writable. Wordpress has a set of standards for files and directories you can find here http://codex.wordpress.org/Changing_File_Permissions
The second could be ownership. You will find that most of the time the owner and the group are www-data. This is dependent on the type of server you are on. If you are operating on cpanel you are owner and group are going to be the username you use to loginto cpanel.
If you give some more info on your ownership and permissions I can help you better.