I believe this is a DW Preference setting issue. Go to DW Preferences > Code Format > Line break type: LF (Unix)
see this tutorial for details on setting up a testing server on mac:
http://www.webassist.com/tutorials/Set-up-a-test-server-on-Mac-OS
and this one for windows:
http://www.webassist.com/tutorials/Set-up-a-test-server-on-Windows