1.) Log into the family account, launch the browser, and then go View->Toolbars and make sure the "parental control toolbar" is checked.
2.) Log out of the family account and into the Admin account, then go into User Accounts and temporarily make the family account an administrative account. Log into the family account and use it to download/install the toolbar. Afterwards log back out of the family account and use the admin account to make the family account a limited account again.
Hope this helps,
P.S. I'm not familiar with that site or toolbar, so I can't comment on its trustworthiness. However, since it can be disabled and/or circumvented by a child this is familiar with computers it should not be relied upon as the first/sole line of protection.
I have windows xp. I have two user accounts: admin and family. the admin level is the only account in which one can download anything. I downloaded parentalcontrolbar.com into my computer, in the admin account (naturally). I can't however, see the toolbar in the family account--so the restricted sites in the admin account can be seen in the family account???!!! What to do?