Read-only records with timestamp

Hi
I have some tables with timestamp field
(timestamp with time zone |  default now()).
It worked well in 7.1.3, but in 7.2.1 the newly inserted records are
read only through the odbc (MS Access, pgAdmin 1.2.0).
I analized the log files and I found that:
on update  or on delete the client sends string like this
'update .... set .... where ... and "idoppont" = '2002-04-26 14:05:17.44'::timestamp'

but

in plsql in same record
the value of the field is  2002-04-26 14:05:17.440044+02

end finally

 select '2002-04-26 14:05:17.44'::timestamp;
timestamptz
---------------------------
 2002-04-26 14:05:17.44+02

What I have to do to eliminate this problem?

Thanks
    Attila Popovics