BUG in 7.1.3

I think I have found a bug in version 7.1.3. (I have installed binary
rpms from postgres site on rh7.1)

Here is the DB and some sample entries.

CREATE TABLE "timetest" (
"id" serial primary key,
"timebegin" time,
"timeend" time
);

insert into timetest (timebegin,timeend) values ('12:00:20','12:01:00');
insert into timetest (timebegin,timeend) values ('14:00:20','14:02:00');
insert into timetest (timebegin,timeend) values ('15:00:00','15:00:40');

WORKS

THIS SELECT DOESN'T WORK:
select sum(timeend-timebegin) as totaltime from timetest;

HERE IS WHAT POSTGRES REPORT:

timetest=# select sum(timeend-timebegin) as totaltime from timetest;
ERROR: Unable to select an aggregate function sum(time)
timetest=# select version();
version
-------------------------------------------------------------
PostgreSQL 7.1.3 on i686-pc-linux-gnu, compiled by GCC 2.96
(1 row)

timetest=#

ON POSTGRES 7.0.3
timetest=# select sum(timeend-timebegin) as totaltime from timetest;
totaltime
-----------
00:03
(1 row)

timetest=# select version();
version
-------------------------------------------------------------
PostgreSQL 7.0.3 on i686-pc-linux-gnu, compiled by gcc 2.96
(1 row)

ascor=#

Hope this can help to fix the BUG!

Alex