Please someone help me! Can't login my page anymore after install this plugin!

Hi!
I can’t access my page as administrator.

I have downloaded this Advertise plugin and since that I can’t access my site any more.

If you go to my page here: http://www.i-dont-know-how-to.com you will see a message above saying “warning”.
But the website still works.
When I tried to access http://www.i-dont-know-how-to.com/wp-admin show up a blank page with the same message.

Don’t know what to do. Does exist Virus Plugins?

I am completly new here. Please someone help me.

http://wordpress.org/plugins/widget-bumbablog-adserver/