In this paper, an overview of the Higgins project and the research within the project is presented. The project incorporates studies of error handling for spoken dialogue systems on several levels, from processing to dialogue level. A domain in which a range of different error types can be studied has been chosen: pedestrian navigation and guiding. Several data collections within Higgins have been analysed along with data from Higgins' predecessor, the AdApt system. The error handling research issues in the project are presented in light of these analyses.