Michelle,
A lot of times when I have had similar connection errors, it has been because I have an incorrect path or root defined within my Dreamweaver site definitions for the testing server. I would probably double check that first. Another thing to check is if you are using a testing server locally - be sure that the server is actually running. I know I have forgot to start mine a couple of times and realized it after trying to connect and getting similar errors.
Warmest regards,
Brian