The fourth column states that the program is listening only for connections on the network interface whose IP address is 127.0.0.1. That means that it's only listening on the loopback interface, so it can only receive connections from the same machine that it's running on, not from other machines connected over the network.
The application presumably has some kind of client-server mode that allows commands to be sent to a running process. TCP is one of the ways to do it.
I hope you didn't block the IP address 127.0.0.1 with iptables, as that is likely to disrupt a lot of things. If you blocked the port used by the program, don't — if it opens the port, it's presumably for a reason.
In any case, blocking traffic with iptables won't close a port. Iptables prevents packets from reaching their destination. It doesn't change anything about whether someone is listening at the destination. You'll still see the port open in
netstat as long as the process is listening.