I think confusion arose when you referred to the file-to-mail operation
as "command line".  To us "command line" means using lcmd or lcmdx to
issue one-line commands to LISTSERV.  The 'mailx listserv < filename'
business is just another mail interface to us, although you're correct,
you run it from the command line :)

If your attempt to send mail to the server to create a list failed then
it sounds like the server is not properly configured to accept mail.
Didn't you say that the message simply sat in the spool and was not
processed?  This usually implies that permissions and/or ownership are
set incorrectly on the lsv_amin program invoked by sendmail to get the
mail into the spool.  (This <is> unix, correct?)  lsv_amin must run
'suid listserv' so that the files it creates in the LISTSERV spool
directory are owned by 'listserv' and have appropriate permissions
such that 'listserv' can read and write them.  This means that lsv_amin
must be owned by 'listserv' and have permissions 4755.  (Assuming that
you installed LISTSERV per the instructions in the installation guide,
ie with 'make install', this should have been done automatically.)

So the big question at this point is whether or not the server can
even accept mail.  Can you send mail to listserv@ your server and
get a response?  If not then you need to look into the issues raised
in the paragraph above.

Nathan