Not closing after run - Address already in use

Using 96.742.

I can run the first time fine, but any subsequent runs I get this:

/opt/local/Library/Frameworks/Python.framework/Versions/2.6/bin/python2.6 manage.py runserver 8000

Validating models...

Error: [Errno 48] Address already in use

0 errors found

Django version 1.2.1, using settings 'tabs.settings'

Development server is running at http://127.0.0.1:8000/

Quit the server with CONTROL-C.

Process finished with exit code 1

I can change the port and it works again first time...

Not sure what I've done as nobody else is reporting this error!