"Cache lookup failed for function" when recreating procs

Env: Windows XP sp2
Version: 8.2.1

I'm attempting to write a function which produces a script. The script
will contain steps necessary to drop/recreate all the functions. I've
got a helper function called 'dropprocsbyname' which takes a schema and
a proc name, finds all matching pg_proc rows and executes 'drop function
xyz' on them.

So the output of my 'recreate all procs' function looks like this:

select * from common.dropprocsbyname('common','proc1');
create or replace function common.proc1() returns bool as
$$body$$
etc
$$body$$
language 'plpgsql' volatile;

etc.. for each proc in the common schema.

I get many, but not all, errors like this:

"psql:e:/pgla_export.txt:1208: ERROR: cache lookup failed for function
22542
CONTEXT: PL/pgSQL function "dropprocsbyname" line 23 at execute
statement"

with the same function oid each time.

When I rerun the script, the oid in the error changes. So, I'm guessing
that it has to do with dropping/recreating my "dropprocsbyname"
function, but I cannot figure out when its being cached and how to
overcome the error.

Chris Fischer
Database Engineer