Vacuum errors and warnings

Ever since I upgraded to 7.0 or 7.1.3 (sorry can't remember which one), I've
been getting notices from the vacuum command about overflowing proc
registers and invalid pointers that didn't appear before. I was just
wondering if this was normal, or if I have something configured wrong. I'm
starting the postmaster with
/usr/local/pgsql/bin/postmaster -B 212890 -N 256 -i -o "-F" >
/var/log/postgres 2>&1
The machine is dual proc, 2GB RAM, RH Linux 6.2. (A secondary question I
have here is whether -B specifies the total amount of RAM to be used for
buffers for all postmaster processes, or the amount of RAM for EACH process.
If for each, then this number is way to high in my case.)
I'm running "vacuum" first with no arguments, then "vacuum analyze". I'm not
sure why I'm doing that, but I vaguely remember in an earlier version of
postgres, the vacuum analyze command would sometimes never complete, unless
I ran vacuum with no args first. Maybe it no longer behaves this way.
Anyway, the messages are...

Vacuuming
(These messages I receive every night)
NOTICE:  RegisterSharedInvalid: SI buffer overflow
NOTICE:  RegisterSharedInvalid: SI buffer overflow
NOTICE:  InvalidateSharedInvalid: cache state reset
NOTICE:  RegisterSharedInvalid: SI buffer overflow
NOTICE:  InvalidateSharedInvalid: cache state reset

(These messages or similiar messages about invalid pointers, I'm sure I
started receiving after
upgrading to 7.1.3 and they occur less often, maybe once every two weeks. A
couple weeks ago, I received messages somewhat similiar to these upon doing
a query upon certain tables, and I had to rebuild the database from
backups.)

NOTICE:  Rel r_maryland: Uninitialized page 730 - fixing
NOTICE:  Index cfsoidmaryland: pointer to EmptyPage (blk 730 off 4) - fixing
NOTICE:  Index cfsoidmaryland: pointer to EmptyPage (blk 730 off 8) - fixing
NOTICE:  Index cfsoidmaryland: pointer to EmptyPage (blk 730 off 6) - fixing
NOTICE:  Index cfsoidmaryland: pointer to EmptyPage (blk 730 off 2) - fixing
NOTICE:  Index cfsoidmaryland: pointer to EmptyPage (blk 730 off 5) - fixing
NOTICE:  Index cfsoidmaryland: pointer to EmptyPage (blk 730 off 7) - fixing
NOTICE:  Index cfsoidmaryland: pointer to EmptyPage (blk 730 off 1) - fixing
NOTICE:  Index cfsoidmaryland: pointer to EmptyPage (blk 730 off 3) - fixing
NOTICE:  Index cfsmakemaryland: pointer to EmptyPage (blk 730 off 3) -
fixing
NOTICE:  Index cfsmakemaryland: pointer to EmptyPage (blk 730 off 6) -
fixing
NOTICE:  Index cfsmakemaryland: pointer to EmptyPage (blk 730 off 2) -
fixing
NOTICE:  Index cfsmakemaryland: pointer to EmptyPage (blk 730 off 4) -
fixing
NOTICE:  Index cfsmakemaryland: pointer to EmptyPage (blk 730 off 5) -
fixing
etc...
(snipped the other 5 pages of these notices)

Thanks much,
Rich