My friend has a guestbook, and he cant get it working on my server that i host him on: http://c0dehax.net/site/Guestbook/guestbook.php

It works on our localhost our computers are windows, but this server is debian linux, i cant figure it out... I dont know much php... but it dont use mysql it writes to files, they are chmodded 777 but i dont know.

Got me, it could be a few things. You can't tell much from the web page/form other than it looks normal from what I can see, except when you click the link to sign it, nothing changes. Perhaps it can't open a template file or something and the script isn't well coded to actually warn you of any problems, the file it can't open or whatever.

Any script should do what it's supposed to and output some error or notice or something, if it fails to do what it's supposed to. You also might not need to set permissions to chmod 777 and can perhaps use a safer setting, if you're on a shared server with out some special means to prevent other users from accessing your directory (for read, write or modification reasons). Put in some error checking on the function/calls, etc. and check your paths and whatnot. To help more, I'd need more information.

isnt it working?
http://c0dehax.net/site/Guestbook/guestbook.php

It works for me.