index quattro problem?

[wenode@perelandra.cms.udel.edu (Vinod Arekar)]

I'm a member of this list (I get the digest regularly), but when I sent
mail to Majordomo with the following body
index quattro
help
end
I got this message back:
>>>> index quattro
**** List 'quattro' is a private list.
**** Only members of the list can do an 'index'.
**** You aren't a member of list 'quattro'.

Is this a known problem?

Vinod