nnml directory customization

[romeomedina]

Hi.

If I put in my ~/.gnus.el the following:

(setq gnus-select-method
      '(nnml ""
        (nnml-directory "/path/to/my/nnml/directory")))

, everything seems to be all right: I get no error messages.
Instead, if I first put the following line:

(setq my-nnml-directory "/path/to/my/nnml/directory")

and then:

(setq gnus-select-method
      '(nnml ""
        (nnml-directory my-nnml-directory)))

, when starting gnus I get the following error message:

nnml () open error: ''.  Continue? (y or n)

. Why? Any idea?

Thanks,
Rodolfo