The process of transferring PhotoBucket pictures to our server has been completed. This means that all posts that the last week has shown "Third party hosting has been disabled" image, now show the correct pictures again. During this process we also downloaded all other pictures linked to the forum from other services, as its better to be safe than sorry. If anyone is curious about how we automated this process, please take a look on this blog post: http://blog.kaizen-web.com/php/how-to-automatically-download-linked-photobucket-images/
Well done! I hope many other forums pick up on your lesson and implement the same transfer. Spread the word to more than a dozen sites.