Hi I am doing a robot simulation project and I am quite a newbie in Player/Stage

When I run the program written my my seniors,i go the following error:

playerc error   : got NACK from request
playerc error   : failed to get response
Could not connect to sonar proxy
SonarProxy::SonarProxy()(-1) : could not subscribe
terminate called after throwing an instance of 'PlayerCc::PlayerError'

Is this because there is something wrong with the configuration files?
The player version i am using is 3.1.0 and stage is 4.1.1.