CACHE ERROR: Could not make directory "thumbs" writable.
You have "cache thumbs" turned on, but your server does not allow the script to modify or create the folder.
Please create the folder "thumbs" and make it writable (quicker), or turn off "cachethumbs" (slower).

GD ERROR:
It looks like your PHP setup is missing GD... Please install it.
Please see http://www.php.net/manual/en/book.image.php for more information.

If you are sure it is installed, and this is an error, you can bypass this by disabling "checkGD" in the config.