He means that he is there for you as a friend and if you have a problem he will be glad to assist you. He isn't asking you to call him just to chat or to hook up, he is just being nice and acting like a gentleman to you.
According to me it is not a good symptom. You may be a charming,talkative and innocent girm. Some guys may try to take advantage out of your innocense. Be careful while dealing with such guys.
If a girl say's that, "Call me if you need me" it means that, for help you can me. If a guy say's that, "Call me if you need me" it may be to, get a friendship or to get some discreet relationship with you.
