Recursive error messages?

I just tried to post to a d-list I created -- let's call it "foo" -- and got this error message:

Your mail for foo@lists.qatar.cmu.edu could not be sent:
no list named "foo" is known by lists.qatar.cmu.edu

For a list of publicly-advertised mailing lists hosted on this server,
visit this URL: [redacted]

If this does not resolve your problem, you may write to:
postmaster@lists.qatar.cmu.edu

So I wrote to postmaster@lists.qatar.cmu.edu... and got THIS error message!

Your mail for postmaster@lists.qatar.cmu.edu could not be sent:
no list named "postmaster" is known by lists.qatar.cmu.edu

For a list of publicly-advertised mailing lists hosted on this server,
visit this URL: [redacted]

If this does not resolve your problem, you may write to:
postmaster@lists.qatar.cmu.edu

Errr.....