the server redirect extesnion is a part of Digital File Pro.
Did you uninstall DFP 2, then install DFP 1? If so, you must delete the Dreamweaver Cache file from the users configuration folder:
common_installation_issues.pdf
An alternative to uninstalling 2 to install 1, then back again is to create a new computer user.
Log in as the new user and install the older versions of the extensions under that user, the only extra legwork you will need to do in this case is to recreate the Dreamweaver Site Definitions. You can simplify that process by exporting the site settings. Go to Site -> Manage Sites. Select the site you wish to export the settings for and click the export button.
This will allow yo to have Digital File Pro 2 installed under your main computer user. When you need to edit a DFP 1 site, log off of the main user account, and log into the second user account where DFP 1 is already installed.
I have only run into slight problems using this method that where always cleared up by deleting the Dreamweaver Cache file from both users configuration folders.