Warning: Function_exists()

After a couple of minutes of refreshing a page, the clock slows down its updating, and the clock ends up 10-15 minutes behind. In trying to troubleshoot why this was happening I discovered that on the Clock Block administration page, a clock was showing up twice in the region. But in the actual theme, on the web, the clock was only being displayed once (which is what is expected).

When I went to delete the duplicate clock in Admin>structure>blocks they both disappeared from the listing (and from the themed page). Which is what I was expecting.

Anytime I access this block (and only this block) I get his warning:

Warning: function_exists() expects parameter 1 to be string, array given in _form_builder_handle_input_element() (line 2024 of C:\inetpub\wwwroot\includes\form.inc).

I've also attached a screenshot.

I'm not sure if this error is connected to why the clock keeps slowing down, but perhaps it is.

Help?