Directory "not writable"

[cleverbum]

I've got quite a large gallery, but recently I tried to add a new gallery only for it to tell me that all the directories were now "not writable" what have I inadvertantly changed to mess this up, and how do I fix it?
When try to add the photos anyway it says "Warning: the script can't write in this directory, you need to change its mode to 755 or 777 before trying to add the files !" how do i do that???

[Sami]

if your web server is  Apache (linux or unix base) you could use your ftp client to change the permission just right click on that folder and select permission (also you can use windows explorer as a ftp client , first enter ftp.yoursite.com to address bar and then from file menu select "login as.." and enter your username & password then right click on that folder and select properties from there you can change permissions)
and if your web server is IIS (windows base) you should ask your hosting support to that for you ...

[Joachim Müller]

There are detailed instructions on permissions inside the docs for cpg1.4.x, link available at the top of this page. They are valid for cpg1.3.x as well.