import data from openoffice Calc

Hi,

I use OpenOffice Base as the front end tool to connect a postgreSQL server.
It works great. But when I am trying to create a table by copying data from
OpenOffice Calc and then pasting to my postgreSQL database (connected
through OpenOffice base), I always got an invalid input syntax error for
type "date". My original data showing in Clac is "12/17/99", but when
OpenOffice base tries to insert this data into a table, it became "36509".
The actual error is as below, can anyone help me to fix this problem. Thanks
a lot.

pq_driver:[PGRES_FATAL_ERROR]ERROR: invalid input syntx for type date:
"36509"
(caused by statement 'INSERT INTO "public"."DF" ("STK_NO","Date","Comments")
VALUES ('11','36509','small inversion'))

LW