This panic is raised by the Read...() member functions and the Advance() member function of TResourceReader, when the current position in the resource buffer is moved beyond the end of the buffer.
It means there is some problem with the resouce. In fact, SetAknEditorSpecialCharacterTable() is expecting a Dialog resource. It is not well documented in the SDK, therefore here is a working example and some note about the usage.
Special character table dialog is inherited from Eikon dialog. It consists of heading pane and character map control. If there are more special characters than what can fit in the one page, scroll indicators are shown.
Special character table supports two character sets: Upper case and lower case character sets. Character sets are read from a resource file. Avkon resource file contains default character sets. An application that is using Edwin editor can set editor specific character set by setting own special character dialog resource to Edwin's special_character_table resource.