Have a couple suggestions for you.

I *believe* that if you modify the AppSetting in your web.config and setthe UsePortNumber node to false, then DNN will stop parsing port numbers in your portalaliases and you will be able to log in and modify your portalaliases manually.  Look for a node that reads:

<

add key="UsePortNumber" value="True" />... And change the value to false. 

If you can't connect after this web.config change, you'll probably have to modify your PortalAlias table manually.  Open your database, and look for the table with this name.  In it, you'll need to modify one or more of the values in your HTTPAlias fields, removing the port.  So if your portalalias reads: localhost:30000/foo, you'll need to make it localhost/foo.  If you prefer, you could add a new entry without the port, and keep your old ones.  Once you're able to access your site again, you can use the UI to make further changes.

Hope this helps!  PortalAlias problems can be frustrating to straighten out.