First of all, there's a forum specifically for Mac OS X Server here -- probably best to ask question concerning Mac OS X Server over there...
Second of all, you haven't provided us nearly enough information to be able to even begin to help you. It could be anything from a network cable that's unplugged, to you not having enough priveledges to do the operations you want, to anything else that pops into our heads.
What version of Mac OS X Server are you running? What kind of machine are you running it on? Have you done any manual tinkering with config files or have you used the GUI to configure everything? Which exact services won't start, and, have they ever started before? Is this a fresh install of Mac OS X Server, or is this a problem that's affected a server that's functioned normally in the past, but now won't? Any power outages recently? Have you added/modified/removed/changed/fiddled with/kicked/punched/spilled water on/cursed at any hardware or software recently?
Again, please provide any and all pertinent information that you think will help us better diagnose your problem. Simply saying "my server won't work" won't get us very far.