buttonset() Missing error.

JSfiddle post JzE78

This could be possible on latest versions i am not 100% sure. I am checking now. But at home when ever i use the button set function. It returns an error in firebug's console stating the function does not exist. Then it did used to work on jsfiddle i found this on a wikia site. i thought it was outdated but after a while the jsfiddle test post starting not working. Now its not working at all. All files are stated in the post and such.

I can not view current errors here at school. But i will when i get home and ill update this. if i can. If this is a bug that was fixed in later versions of UI or / Core Please tell me so i can inform the wikia admin of this. But for now the bug just started occuring in jsfiddle.