All, I have a MySQL table "category" with the following schema: id number name char parent_id number The table is self-referencing in that the parent_id points back to an ID. This structure renders a hierarchical listing of categories, with the root categories having a parent_id of -1. I have a SQL method to select category names and IDs by their parent ID: ID: Query_category_by_parid Arguments: parent_id:required:int Query: select id, name from category where <dtml-sqltest parent_id type=int> order by name I have a DTML method which calls itself recursively to find a list of categories starting with the specified parent: ID: list_categories <dtml-in "Query_category_by_parid(parent_id=parent_id)"> <p><dtml-var name> (<dtml-var id>)</p> <dtml-var "list_categories(parent_id=id)"> </dtml-in> This however, doesn't work. It appears that the second call to Query_category_by_parid, within the second call to list_categories, fails. Here is the URL: /list_categories?parent_id=-1 This is the error I receive: Error Type: NameError Error Value: Query_category_by_parid And here is the traceback: Traceback (innermost last): File /usr/local/src/Zope-2.0.1/lib/python/ZPublisher/Publish.py, line 214, in publish_module File /usr/local/src/Zope-2.0.1/lib/python/ZPublisher/Publish.py, line 179, in publish File /usr/local/src/Zope-2.0.1/lib/python/Zope/__init__.py, line 201, in zpublisher_exception_hook (Object: ElementWithAttributes) File /usr/local/src/Zope-2.0.1/lib/python/ZPublisher/Publish.py, line 165, in publish File /usr/local/src/Zope-2.0.1/lib/python/ZPublisher/mapply.py, line 160, in mapply (Object: list_categories) File /usr/local/src/Zope-2.0.1/lib/python/ZPublisher/Publish.py, line 102, in call_object (Object: list_categories) File /usr/local/src/Zope-2.0.1/lib/python/OFS/DTMLMethod.py, line 145, in __call__ (Object: list_categories) File /usr/local/src/Zope-2.0.1/lib/python/DocumentTemplate/DT_String.py, line 502, in __call__ (Object: list_categories) File /usr/local/src/Zope-2.0.1/lib/python/DocumentTemplate/DT_In.py, line 691, in renderwob (Object: Query_category_by_coid_parid(parent_id=parent_id)) File /usr/local/src/Zope-2.0.1/lib/python/DocumentTemplate/DT_Util.py, line 321, in eval (Object: list_categories(parent_id=id)) File <string>, line 0, in ? File /usr/local/src/Zope-2.0.1/lib/python/OFS/DTMLMethod.py, line 141, in __call__ (Object: list_categories) File /usr/local/src/Zope-2.0.1/lib/python/DocumentTemplate/DT_String.py, line 502, in __call__ (Object: list_categories) File /usr/local/src/Zope-2.0.1/lib/python/DocumentTemplate/DT_In.py, line 633, in renderwob (Object: Query_category_by_coid_parid(parent_id=parent_id)) File /usr/local/src/Zope-2.0.1/lib/python/DocumentTemplate/DT_Util.py, line 321, in eval (Object: Query_category_by_coid_parid(parent_id=parent_id)) File <string>, line 0, in ? NameError: (see above) I have a feeling I'm missing something obvious, such as a problem with the namespaces. Any help would be greatly appreciated. Cheers, Jim