pg_dump problem

Dear group,
I have a strange problem. apologies if this is the
wrong place, however as a first option i am posting
here. I have to subscribe to other special mailing
lists.

I have two databases in my system.

In firstdb i am having the following problem:
firstdb=# \d targets
ERROR: could not access status of transaction 362
DETAIL: could not open file
"/var/lib/pgsql/data/pg_clog/0000": No such file or
directory

when I vacuumed it:
$ vacuumdb firstdb
vacuumdb: vacuuming of database "firstdb" failed:
ERROR: could not access status of transaction 11
DETAIL: could not open file
"/var/lib/pgsql/data/pg_clog/0000": No such file or
directory

Second problem:

Issue with secondb - arraydb

$ vacuumdb arraydb
VACUUM

Suspecting there is something going on with postgres,
I wanted to take a backup of the arraydb.

here is what I am doing:

$ sudo pg_dump arraydb > arraydb_bcup_Aug_05_2006.dump

$ ls -lh
total 8.0K
-rw-r--r-- 1 speri postgres 0 Aug 5 20:17
arradb_bcup_Aug_05_2006.out

There is nothing in this. I created dumps long back
and they are heavy.

what could be the problem in the cases of first and
second problems.

looking forward to hear from experts eagerly.

Thanks

__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com