mail-recover seems not working

[Philippe Waroquiers]

In GNU Emacs 21.1.2 (hppa1.1-hp-hpux11.00, X toolkit)

Start emacs with emacs --no-init-file --no-site-file
Start composing a mail with
M-x mail
type enough characters to have the *mail* being auto-saved.
(to make it easier, before doing the mail, the variable
auto-save-interval can be set to a low value e.g. 10).
Then kill the buffer.
It is unclear how to recover what has been typed..
M-x mail-recover 
gives an error message such as:
/net/gull/disc1/home/wao/#*mail*#238869cr# not found

Then, if answering yes to the question, another
error message:
mail-recover: Opening input file: no such file or directory, 
/net/gull/disc1/home/wao/#*mail*#238869cr#