spell: zw/zW doesn't work

[Luis A. Florit]

Pals,

    Are you able to make zw/zW work for the spell feature in Vim 7.0?
For me, they just do nothing. The spellfiles are not changed.
':spellw[rong]! {word}' also doesn't work, it does nothing. 
No changes in the spelling, nor in the spellfile.
There is no file permissions problem with the spellfiles.
zg/zG works fine, as well as editting the spellfile by hand 
and adding '<word>/!' and then ':mkspell! %'.

    I use Fedora Core 5 and the devel rpms 7.0.017-1.

    Is this a problem just with me?

        Thanks,

            Luis.