How do I restore the .zip file
This procedure also present in the KB article which you mentioned.From that KB Article
In the Services window, right-click Symantec Endpoint Protection Manager, and then click Stop.
Note: Do not close the Services window until you are finished with this procedure.
Create the following directory:
\\Program Files\Symantec\Symantec Endpoint Protection Manager\data\backup
Copy your database backup file to the directory.
(This is that zip file)
Note: By default, the database backup file is named date_timestamp.zip.
Click Start> Programs> Symantec Endpoint Protection Manager> Database Back Up and Restore.
In the Database Back Up and Restore dialog box, click Restore.
In the Restore Site dialog box, select the backup file that you copied to the backup directory, and then click OK.
Note: The database restoration time varies and depends on the size of your database.
When the Message prompt appears, click OK.
Click Exit.
Encryption password is the same first password of the console if you selected the option simple while configuring SEPM.If you used advanced option you may given a different one.This password is required only when you do not having a database back up and you need to reestablish the connection with clients.