Administrative commands fail - and owner is removed from the list! 
            
This is the dreaded line wrap problem. 

WARNING! sometimes a subscribe or unsubscribe command will be so long
that your mail program will 'wrap' it, producing two lines instead of
one. If you put a backslash character (\) at the end of the first line,
majordomo will treat the second line as the continuation of the
first. If you are using a GUI based mail client, be sure to press the 
'Enter' or 'Return' key to put a 'hard' carriage return after the
backslash. Eudora and some othe mail clients do a wordprocesser like wrap 
based on the window width while you are entering the text, but inserts 
hard returns at the first white space after column 72 when it actually 
sends the message unless you have turned the word wrap feature off.

so instead of:

approve password subscribe some-long-listname  john_henery_doe@darkwing.uoregon.edu
end

do this:

approve password subscribe some-long-listname\
jonh_henery_doe@darkwing.uoregon.edu
end

The last command should be the single word 'end'. This will prevent 
majordomo from trying to interpret your 'signature' (should you have 
one) as majordomo commands.