I don't get to update my filelists often these days (coowners put the
stuff on their web sites instead and ain't got AFD/FUI anymore)  so I'm a
little rusty, but here's what I think.

You can get that error because there is something odd in the file
and listserv won't accept it.    You could get it because you are
using the list password rather than your personal password and someone
has changed it on you, or you're coming from a nonowner address( ok
for a personal password, no-no for list password).  I did some chaecking,
though and I don't think those, or other maybes, are the problem.
I think your PUT is wrong.

Your list does not have notebooks and seems not to have its own filelist.
Your PETBUNNY WELCOME is in the general listserv filelist.  The FAC for
PUT is MSC with the explanation Miscellaneous- contact administrator for
further information.  So, it's worth another shot, try:

PUT PETBUNNY WELCOME LISTSERV PW=xxxxxxxx

If that does not work contact the administrator and while waiting for an
answer make sure the file has no weirdo stuff (articats from a word
processor program?).  And if you're using the list password rather
personal make sure no one has changed it (I have never used list,
always personal, don't think the lists even HAVE passwords).

If you want your list to have its own filelist your administrator will
have to set it up for you.  If all you use it for is the Welcome, though,
there is little point in it.  Some people like and use filelists, some
don't, if you've no use for it no reason to set it up.

Douglas