Twist Testing Tool with SAHI : Port Numer is already being used

When ever i start running the script i get this error

"--- ERROR: Port 1001 is already being used ---"

Work around :

Change port number to 1002 in sahi.properties file and save it.

Then start running the script after browser opens go to Internet Options-->Connections-->Lan Settings --> change port number  to 1002
Now refresh the page -->Sahi.example page opens and script runs.

Again if we try running another script it  will give same error

"--- ERROR: Port 1002 is already being used ---"

Now change port number in sahi.properties ,browser port number it runs.