modeller usage

Hello, I am a begiiner with modeller. I am using modeller6v2. I tried running modeller with model-default.top as the input file and from what I knew,a '.atm' file has to be generated after the process. I am working in LINUX. The process stopped after a couple of seconds and the message STOP was thrown. No ".atm" file was generated. How do I proceed further? sincerely, somanadh