This file does not exist! I think it was removed some time around beta4?
You are quite right; it seems it was removed by another developer. The server name is now automatically set as the same URL used for accessing vlanPlot itself, however, it can be changed manually by editing:
/usr/local/nav/apache/webroot/vlanPlot/vlanPlot.py
Look for 'vPServerURL' and 'cricketURL'.