I have just over 2 years of AWS EC2 Management under my belt. If you look at my profile, unfortunately this is the first job i have bid on, but I feel more than confident that i know exactly what this issue is. Most likely its a firewall issue, either A. Security Group setting (Most likely this, these gave me quite a few issues.) B. Firewall on the server itself (Possible if you're using a Windows Server OS) or C. (If running linux) Could possibly be a rights issue with the program binding to the correct port on your box.
Anyway as I stated before, I realize i do not have much a reputation on this site. I'm hoping that the information and personal nature of the proposal will be enough. I absolutely love AWS and I sincerely look forward to working with you to fix this issue. Feel free to email me with any questions you have.