Notice: Undefined index: ckeditor in wysiwyg_profile_overview()

It sounds a lot like you've got a profile for CKEditor for one of your text formats, even tho the editor is no longer installed.
The line throwing the notice tries to fetch editor information from a list of installed editors, based on what's set a profile associated with one of the text formats.

Did you have CKEditor installed before but deleted the files in sites/all/libraries/ckeditor before removing the profile?

The table rows listing text formats should have a column with the name of an editor associated with that format, and its version number. If the column is empty, it means the editor is either not installed or not detected properly.
You should have the option to delete that profile even if the editor itself is no longer installed.

Can you please confirm this?

Sorry, but without further information I can only close this issue.
Please reopen it if you still need help.