Message could not be delivered

["The Post Office" <postmaster@xxxxxxxxxxxxxx>]

The original message was received at Thu, 1 Mar 2007 19:34:17 +1100 from groupstudy.com [197.253.77.197]

----- The following addresses had permanent fatal errors -----
<ccielab@xxxxxxxxxxxxxx>

----- Transcript of session follows -----
... while talking to mail server groupstudy.com.:
>>> DATA
<<< 400-aturner; %MAIL-E-OPENOUT, error opening !AS as output
<<< 400

[GroupStudy removed an attachment of type application/octet-stream which had a name of ccielab@xxxxxxxxxxxxxxxxxx]