Have you whitelisted your IP?
By default the databases only allow access from DreamHost domains. You can whitelist your own IP from within Panel.
Go to Goodies > Manage MySQL and click on the username within the "Users with access" field. On the proceeding page you'll see an "Allowable Hosts" edit box where you can add your own IP. Usually your own IP is displayed to the lower left for precisely this reason (and to make things easier).
If you've already whitelisted your IP then I'm afraid I'm out of ideas, but Scott may have some extra instructions as he's really clued up when it comes to Macs, their software, and any quirks involved with getting it all to run happily with DreamHost.
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