Commented Issue: Filtering on Child field [24992]

When I try to put a filter on a child field, I get the following error. Otherwise, it works fine and filtering on a parent field do not have such an issue.

An unexpected error has occurred.
Troubleshoot issues with Windows SharePoint Services.
Comments: ** Comment from web user: masterminx **

I have this same issue. I made tables and configured according to the example on the blog entry here: http://sharepointsircar.blogspot.com/2009/02/cascading-dropdownlist-custom-field.html
If I try to create a new list item or edit an existing one, I get the error described above. I tried to troubleshoot by checking the function of the site one step at a time, and find that the error occurs as soon as I add a child field.