Bug: COUNT() and ExecEvalAggref error

I've looked through my archives of pgsql-general and pgsql-hackers and
haven't seen this, but I do tend to flush the deleted messages
occasionally. I'm trying to get a build off the current CVS tree, but
my working build is from Sunday evening, so I feel moderately current.

Two builds of 7.1beta4 from the CVS tree. The one on my production
machine was built January 29, the one on my development machine was
built from sources gotten Sunday evening.

When I do this:

$ /usr/local/pgsql/bin/createdb test
$ /usr/local/pgsql/bin/psql test
test=# create table abc (id serial, stuff text);
test=# insert into abc (stuff) values ('xyz');
test=# insert into abc (stuff) values ('xyz');
test=# insert into abc (stuff) values ('xyz');
test=# insert into abc (stuff) values ('qrs');
test=# insert into abc (stuff) values ('qrs');
test=# insert into abc (stuff) values ('qrs');
test=# insert into abc (stuff) values ('qrs');
test=# insert into abc (stuff) values ('qrs');
test=# select count(id) from abc;

On my production machine (PosgreSQL built from CVS on January 29) I
get the expected result:

count
-------
8
(1 row)

On my development machine (Built from CVS late Sunday, February 18), I
get:

test=# select count(id) from abc;
ERROR: ExecEvalAggref: no aggregates in this expression context
test=#

Apologies if this has gone by already, I'm in the process of trying to
get an absolutely current CVS update to build and if anyone's got
suggestions on where to start before I dive into the PostgreSQL code
whole hog for the first time I'd sure appreciate it.

Don't think it matters, but just in case, development box is:

Linux wynand 2.2.17 #7 Wed Nov 8 09:47:05 PST 2000 i586 unknown

Production server, and the machine that the production server binaries
were built on, both of which work:

Linux mail 2.2.12 #6 Tue Jan 18 17:49:47 PST 2000 i586 unknown
Linux francon 2.2.18 #2 SMP Sun Jan 28 20:10:18 PST 2001 i686 unknown

All using libc-2.1.3.so

Dan