If the 'History Manger' is empty, then most likelye there are no History Items to manage.
Sorry.. but i can't help ya any further im afraid.
I think you have to wait for JV16, but he is moving atm, and wil be back around next monday / thuesday.
An other thing what i can sugest is this.
Clear the browsers cache, then download the latest version of PowerTools. Uninstall the current version, and make sure that the whole folder where PowerTools whas installed at is gone, if not, remove it yourself.
Then reinstall PowerTools and check what happens.
Hope this will help you atleast a litle bit .