Updating iRite instances does not always remove the WA_iRite include which breaks the page until you find the problem. I am also seeing some instances where the custom toolbar does not exist problem occurring after updating an instance. The first couple went fine, so it may be related to whatever bug also prevents the include from being removed.
Other extensions may have pushed the WA_iRite include further down in the code which may be confusing the update process. The GUI was so buggy, I probably manually inserted the include myself to apply WA_iRite to these pages.