plpgsql no longer exists

Hi listers!
I'll start with some details:

select version();
PostgreSQL 8.0.0 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 3.3.5 (Debian
1:3.3.3-5)

Upon compiling a new function that I was working on, I came across an error:
"could not read block 0 of relation 1663/17239/16709: Bad address" which was
being triggered by my trying to compile my function.

The relation in question turned out to be pg_language. I reindexed that table
and the "could not read block..." error went away, then I started to get the
"...language "plpgsql" does not exist..." (as shown after the following function):

-- note, this is only a test function, but it yields the same error:
dev=# create function text() returns void as $$
dev=# begin
dev=# return;
dev=# end;
dev=# $$ language plpgsql;
ERROR: language "plpgsql" does not exist
HINT: You need to use "createlang" to load the language into the database.

I then issued a "createlang plpgsql <this_db>"

-- checked the pg_language table at this point (which I probably should have
done before I went and ran the createlang command)

dev=# select lanname,lanplcallfoid,lanvalidator from pg_language;
lanname  | lanplcallfoid | lanvalidator
---------------------------------------
plpgsql     |         17811 | 17812
plpgsql  |         17811 | 17812
internal |             0 | 2246
c        |             0 | 2247
plperlu  |         17808 | 0
plperl   |         17808 | 0
sql      |             0 | 2248

Apparently plpgsql does exist. It also now had duplicate entries for plpgsql. I
replaced the contents of the table with the all of the same values, minus one of
the duplicates and reindexed it. I restarted my postmaster, and the missing
language error went away.

Now when I am running any function, I am getting:
"ERROR: cache lookup failed for language 17813" (or occasionally, 17810 or 17809).

Once I recompile the function, I no longer get that message. Is there anything
else that I can check or do to make this stop happening? Or is this a sign of
things to come (possible corruption, etc?)

Thanks for any help!

Cheers,

Bricklen