On our MOSS farm, I'm trying to modify my SiteDirectory list. Alas, I
can't, as when I try and edit it, I get this pop-up error:

Line: 855
Error: 'helperFrm' is null or not an object

Google returns one usable page:

forums.microsoft.com/.../ShowPost.aspx

which pretty much asks the same question: What in the hell is this?

Any ideas?

This is kind of a big deal as it makes every single list on our farm uneditable.