OK so my previous post was for getting subtext running on your local vista machine. but this is no good if you cannot connect to your database. So what you can do is create a new Database in your SQL 2005 Express instance on your computer or make a back up of your live database and then restore that on your local computer.
Creating a new Database is very simple. load up the SQL Server Management Studio Express and login as your sa account:
Once logged in right click on Databases and select new.
for the example I have called my database Subtext_offline. Click on ok and that is your database created.
Make sure that your web.config has its data connections pointing to your localhost and the new database. If you are wanting to create a new database then all you need to do is load up your offline subtext in your web browser and go through the installation process. If you want to have a copy of your live database you will need to make a backup of it and then restore over your local Database.
to make a backup you wil need to use the management tools your hosting company use, they are usually pretty straight forward to do. Once you have made a backup of it save the backup file to you local computer.
Right click on the Database that you created and go to the following option:
Select From Device
Click Add and then browse through your computer for the backup file
Select the File and then click on OK
Click on OK again
Check the option to restore the Database
Then click on the 
Make sure that you set the restore paths are set to something that exists on your computer as the backup sets may contain the paths that they existed on on the live server.
Also make sure that you Check the Overwrite the existing database option other wise you will not ba able to restore it.
once you have done that you will then have a copy of your live database on your offline site.
