the problem may be
1. in your ISP
2. in your router
3. on your PC
4. in HFS
how to face the problems above
1. start changing your port with something higher like 35000. if it still doesn't work, ask your ISP if they are blocking you some way.
2. if the ISP is not the problem, you should determine if it is HFS or not. try with another web server, on the same port. if it doesn't work (through the internet) either, then you know the problem is in router or PC.
as "another web server" you may try
baby web server. It is very compact and should be fine for a test.
3. to know if it is your PC or router, you can try killing/unintalling any software that may virtually interfere with the connection. (firewalls, limiters, loggers, antivirus, etc). If a clean PC doesn't communicate, it is likely that the router is guilty.