Cann't connect to my iMac over another Wi-fi

I set up my iphone to connect to my home wi-fi using the recommended instructions. But I wanted to try to control my imac over another wi-fi connection, when I tried to connect using another wi-fi connection, I got a problem on my iphone saying that my imac has blocked the connection because of the firewall.
In addition, I searched google, I looked up in the FAQs, and I need help.

I’m Running 10.5.6
I have jaadu vnc connect ( it shows Sharing on )
I have Vine-Jaadu Server v1.2 running, my home wi-fi ip’s shows up green and it says Internal, likewise, the other outside wi-fi connection I was trying to test on shows up in red and External.

Thank you in advance.