Insert/select union bug

[Peter <peter@xxxxxxxxxxxxxxxx>]

create table temp(a timestamptz);

insert into temp(a) select NULL; /* this passes */

insert into temp(a) select NULL union select NULL; /* fails:
ERROR: column "a" is of type timestamp with time zone but expression is 
of type text
*/

I need to insert hundreds of thousands of rows, and insert into ... 
select union is by far more efficient than multitude of inserts.

Postgres 8.1.3, FreeBSD.

Has this (maybe) been fixed in most recent release?


Peter