If you have used this method to install openmrs Setting of OpenMRS development environment and getting started up then this trouble shooting might be required.
In my case:
This stack trace means that there is some process running on localhost:8080/ , in my case it was the tomcat server which I installed while setting up openmrs.
There is a useful post here: http://stackoverflow.com/questions/4071817/how-to-shutdown-tomcat-in-ubuntu
Now reboot the system and try running openmrs in the normal way. It wll work this time.