Is the server installed under program files? If so, stop the service. uninstall the service move the install directory out from program files to a directory path with no spaces reinstall the service start the service. Hope this helps. There is a more detailed explantion in another thread. Search for jpostedc and you should find it.
the "provider not yet setup" message means the agent has not been configured with the IP and port of the server yet. This tends to happen in Windows environments because you are probably starting the agent via Windows Service. Try starting the agent in a command line window and see if it starts up. Once you start it on the command line and everything is working, you should be able to use the Windows Service from that point on.