/etc/fstab error and I can't start the system normally

[micman]

I think that the problem was a damaged  system. I have re-installed 
FreeBSD  and now ALL the commands and methods work.

mount -u /
or
mount -o rw /
and I can access to the root directory

I mount /usr and I can use ee  (effectively a nice editor)

ee /etc/fstab (absolute path isn't necessary)

I have tried  "Fixit" and the result  is the same (here the absolute 
path is NECESSARY).

For a non-experimented user --like me-- "cover the bases" is the most 
important thing to begin.  I couldn't rescue my old system but now I 
know a little more.

Thank you very much.

micman