I see what happened... since Tom responded to the thread just before I created the incident, it got created for his profile instead of yours.
Here is the fix and instructions:
I have attached a zip that contain two files to fix the issue with Security Assist Authenticate User.
Please download the attached file and place the files at this location:
Hard disk: Users: <Your User Name>: Library: Application Support: Adobe: Dreamweaver CS4: en_US: Configuration: Commands
Make sure to have Dreamweaver closed and delete the MacCache file before restarting.
Please post back with the results.