This might help test is your VNC port is responding...

Try telnetting from your home to your office and vice versa using:
telnet ipaddress 5900

You should get some characters back, I got "RFB 003.003". You can pretty much use telnet to test most ports.

And agreeing with others, I would NOT have VNC exposed to the Internet as there are a some crackers out there AND the initial password is transmitted in plain text.