Posted on 9-4-2013
It looks like you have followed an old or broken link to remove the banner of your plugin. Once you finished your donation process an url will appear with the link to remove your banner, just follow it and you get your code to get rid of that pain in the ass.
If you have already donated for any other site, you don't have to donate again, just contact me and I will send you the correct URL to get your banner removal code.
If you didn't donate, consider to do it, donating even 1 cent will remove the banner from your installation, and you will be helping Custom Sidebars to get better.