@PramitKumar Pal Did you do what the dialog box says? edit /home/username/.gaw/gawrc and ensure the following line is present and not commented. If not present add it.

up_listenPort = 2020

Also ensure no firewall is blocking local TCP connections on port 2020

yes I did change the up_listenPort to 2020. Gaw opens up when I click on waves but it throws this error when I try to send a wave to it after simulation