Weird Errors in 6.4.2 - Indexes/Vacuuming

It seems there are some pretty critical problems in the indexes and/or
vacuuming code in PostgreSQL 6.4.2. I've mentioned this before, but never
get any clues back.

Here are some error codes that I get almost every nite when I vacuum....

NOTICE: AbortTransaction and not in in-progress state
ERROR: heap_delete: (am)invalid tid

...And...

NOTICE: Rel pg_statistic: Uninitialized page 2 - fixing
ERROR: Tuple is too big: size 15248

Can anyone please shed some light on this? I don't have any code that would
be creating tuples bigger than 8100k, so the 15248 is not possible.

In addition, the "tuple is too big" error goes away in the second vacuum.
It's there one night, but not the next, and I never delete records out of
this database. The first errors up there require me to drop the indexes on
this 3GB table and rebuild. That's a pain.

Tim Perdue
PHPBuilder.com / GotoCity.com / Geocrawler.com