Upon activation returns an error message: Warning: Creating default object…

So when I download and activate this plugin I get the following error message:
Warning: Creating default object from empty value in *my-wordpress-installation-folder*\wp-content\plugins\hide-wp-toolbar\hide-wp-toolbar.php on line 119
When I look at the mentioned line I see that this is part of something session related. I could not detect anything that might be wrong, though my PHP knowledge could use some improving.
I run my website for testing purposes on a local server with EasyPHP, is it possible it has something to do with this?
If so, could I maybe remove the session option, to keep using this plugin? If yes, how (again, my PHP knowledge is really lacking)?

A pity this has to be so complicated. When working it seems so perfect.

http://wordpress.org/plugins/hide-wp-toolbar/