>    ERROR: hostname:/partition does not support CALCSIZE for estimate,
> using CLIENT.
>       my two clients are 2.4.3 and 2.4.4p1 are these two clients too
> old to support the calcsize option.
 
I don't know.  Maybe someone else will have the answer, or maybe there
is a changelog on the website which lists when this feature was added.

> I can not use estimate server since these two filesystem have never
> been backed up by amanda and so the server can not provide an
> estimate, correct.
You can still use server, its just that your first estimate will be
completely wrong.  I can't remember what it uses off hand (zero?), but
it works fine.  I do it all the time when I add a new disk.