t-sql error

I am new to t-sql in the last few months. I am getting the following error in sql server 2005 and would like to know how to get around the problem:
Msg 4104, Level 16, State 1, Line 1
The multi-part identifier "Z.MaxReceiveDate" could not be bound.
The sql that I am running is the following:
select distinct Z.gnumber, R.Requests, Z.MaxReceiveDate

from

(select distinct gnumber,
count(*) as Requests
from dbo.table1
where receive_date > Z.MaxReceiveDate
group by gnumber
) R

left join
(select distinct P.gnumber,
MaxReceiveDate = Max(Received_Date),
from dbo.table2
group by P.gnumber
) Z
On Z.HNumber = R.Hnumber
I am bascially trying to use the maxreceivedate value from a subquery.
Can you suggest ways to solve this problem?
Thanks!

This post is duplicated and answered at
http://sql-server-performance.com/Community/forums/p/31428/163585.aspx

Moderators, Can you please do your magic and lock this thread? Thanks,