I understand your point. The reason that i told you to rename your configuration folder, because that fixed the issue with the javascript error messages. But you can try uninstalling Site Import first, and then browse to this location:
--Hard disk: Users: <Your User Name>: Library: Application Support: Adobe: Dreamweaver CS4: en_US: Configuration: Shared: WebAssist:
and delete the ImportSite folder. Then Install Site Import (Make sure to select Yes to All), delete the cache file and then start DW.