roscore launch failed saying "You must specify a valid interface name"
I installed ros groovy recently, and now I got this error frequently when I use command "roscore":
... logging to /home/jingru/.ros/log/52f1ef44-c93e-11e2-8e1d-648099590658/roslaunch-Jingru-Lenovo-11463.log Checking log directory for disk usage. This may take awhile. Press Ctrl-C to interrupt Done checking log file disk usage. Usage is <1GB.
started roslaunch server http://Jingru-Lenovo:38033/ ros_comm version 1.9.44
SUMMARY
PARAMETERS * /rosdistro * /rosversion
NODES
You must specify a valid interface name.
After a system reboot, I can launch it successfully. Please help! Thank you in advance.