Error in search

[hengistthenord]

on a 2.4 install from package Ubuntu 12.04 I have
Module ckan.controllers.package:270 in search

query = get_action('package_search')(context, data_dict)
Module ckan.logic:429 in wrapped
result = _action(context, data_dict, *_kw)
Module ckan.logic.action.get:1951 in package_search
search_results = item.after_search(search_results, data_dict)
Module ckanext.searchhistory.plugin:42 in after_search
result = tk.get_action('search_history_add')(context, data_dict)
Module ckan.logic:429 in wrapped
result = _action(context, data_dict, *_kw)
Module ckanext.searchhistory.actions:45 in search_add
return db.table_dictize(search_history, context)
Module ckanext.searchhistory.db:67 in table_dictize
if isinstance(obj, sa.engine.base.RowProxy):
AttributeError: 'module' object has no attribute 'RowProxy'

removing the plugin and removing it from the plugins list in production.ini solves the 500 error and site now shows search results again