something has happened to all your folder file permission settings.
Refer to the install guide for reference.
https://www.ubbcentral.com/doc_install.php Set File & Directory Permissions
Linux, Unix, and Mac Servers:
You must set the following permissions on the UBB.threads files and directories. You can use your FTP software to set these permissions. For exact information on setting permissions in your FTP client, see the documentation included with that program.
admin/ directory: set permissions to 777
files within the admin/ directory: set permissions to 666
cache/ directory: set permissions to 777
cache_builders/ directory: set permissions to 777
cache_builders/custom/ directory: set permissions to 777 (Required to edit Custom Islands)
files within the cache_builders/custom/ directory: set permissions to 666 (Required to edit Custom Islands)
gallery/ directory: set permissions to 777 (Required to use the Gallery feature)
directories within the gallery/default directory: set permissions to 777 (Required to use the Gallery feature)
includes/ directory: set permissions to 777
files within the includes/ directory: set permissions to 666
languages/ directory: set permissions to 777
languages/english/ directory: set permissions to 777
files within the languages/english/ directory: set permissions to 666
languages/english/admin/ directory: set permissions to 777
files within the languages/english/admin/ directory: set permissions to 666
sessions/ directory: set permissions to 777
styles/ directory: set permissions to 777 (Required to use the Style Editor)
files within the styles/ directory: set permissions to 666 (Required to use the Style Editor)
templates/compile/ directory: set permissions to 777
templates/default/ directory: set permissions to 777 (Required to use the Template Editor)
files within the templates/default/ directory: set permissions to 666 (Required to use the Template Editor)
tmp/ directory: set permissions to 777
uploads/ directory: set permissions to 777
Note: Some servers will not allow scripts to be executed out of a directory that is has 777 permissions, such as the dashboard.php file in the admin directory. If this is true on your server, your UBB.threads forum directory and the admin/ directory should be chmodded 775 or 755 with the files in the /admin directory chmodded 644.
suPHP with a allow_file_others_writeable value of disabled may generate lines containing "is writeable by others" to the error logs.
Where it generally isn't used by most forums, you can manage images in the control panel if you chmod the files and directories within the images/ directory appropriately (777 for directories, 666 for files).