Can't edit tables with timestamps

Given a database created from the following SQL:

CREATE TABLE "testtable" (
        "id" integer NOT NULL,
        "mytext" character varying(32),
        "mytime" timestamp with time zone,
        Constraint "testtable_pkey" Primary Key ("id")
);

COPY "testtable" FROM stdin;
1       \N      2002-03-27 20:15:52.000000+00
2       \N      2002-03-27 20:16:05.187532+00
\.

You will find that whilst the 1st record can be edited using pgadmin, any
attempt to edit the 2nd results in the message "Could not locate the record
for updating in the database!" when you attempt to save your changes.

Presumably this is something to do with the non-integer seconds part of the
timestamp in the 2nd record. Unfortunately the timestamp in this record is a
"real" timestamp created using the now() function, ie typical of real-world
data...

--
Thomas Sandford | thomas@paradisegreen.co.uk