[Twisted-web] How to free port 8080?

I have deleted all .tap files in the work directory(a *.tap would use 8080?),then "mktap telnet -p 8080 ..." and "twistd -f telnet.tap",testing on "telnet localhost 8080" get message as the following: ...... 2006/12/30 14:31 CST [-] twisted.internet.error.CannotLi stenError: Couldn't listen on any:8080: (98, 'Address already in use').

How to free the port 8080?