You don't provide much information to go on. It could be a lot of things. Did you go through the configuration of xinetd? And restart it? Check out the comments on this thread http://forums.zmanda.com/showthread.php?t=351
, and check through the suggestions in this troubleshooting guide http://wiki.zmanda.com/index.php/Sel...request_failed
When you post a question, try to provide a little more information to give your question context. Your distribution and the Amanda version might be useful. What you have done so far in the installation, what worked and what didn't, what you've tried, resources you've checked. If you have a working setup and are adding a client. Whether you have other clients and whether they work. All of that can be useful in getting help. Otherwise, we are just waving our arms and thinking about listing all the possibilities whether they are pertinent or not.