The error means the same what it says,
"you cannot run 2 instances of server on the same port".
in this case,it can be another project of yours that might have used tomcat previously and hasn't leaved it yet.
solution:
# if you are not sure if your port are currently being used ,
*either visit the link
http://localhost:8080/ on your browser.If you get to the
server's homepage or see a typical 404 error,
your connetion is being used.
*or simply type the command netstat -a in terminal(linux) or command
prompt(windows)
it'll list down all the ports open/listening on your machine.
# once you get to know that the port you want to use is already in use,
*either shutdown the system(which will automatically free the ports) //bad option
*or change the ports 8001,8080,8009 from server.xml file
//u'll find it inside /conf directory of tomcat folder.
*or traverse to the place where you have installed your Apache Tomcat
go to /bin folder and execute the shutdown.bat file(windows) or shutdown.sh
file(Linux).it'll close your server and thus freeing the ports which were in use
open eclipse again and restart the server
regards,
Nalin_C