Tabbed Widgets not working with v 2.8 update

When I upgraded my blog to v.2.8 my tabbed-widgets sidebar disappeared.

It still shows up in my plugins menu, and I can still alter its components and settings in the appearance menu, but it does not show up anywhere on my blog’s sidebar.

Any Ideas? Anyone else had this problem?

I will be happy to provide any necessary code that is requested.

Thanks.