In your account, I see you have a Slingbox PRO-HD.
The administrator password in your Slingbox is the one you created when you last ran through the setup process for that Slingbox. If that password has been forgotten, you will need to factory reset the Slingbox and run through the setup process once more. Here is some information on how to reset the Slingbox:
After factory resetting the Slingbox, use a computer connected on the same network as your Slingbox to go to setup.slingbox.com and run through the Slingbox setup process.
Hope this helps!