Upgrading from 6.3->6.4.2/6.5b1 possible

AHH! The pgsql v6.3 backend has begun crashing horribly on me since I've
added a few more database backed webpages (with messages like 'backend
cache invalidation...').. I figured that upgrading to 6.4.2 would solve my
problems.. But I can't upgrade! Things I've tried:

* Using old pg_dumpall -z > file and psql -e template1 < file (after
install and initdb)
* Using the pg_dumpall from the new version.
* Using pg_upgrade
* Rereading the docs dozens of times
* having a friend try it.
* all of the above with both 6.4.2 and 6.5beta

Every time I start loading, it chokes up on the dump output and falls into
a constant stream of parse errors and messages like "PQsendQuery() --
query is too long. Maximum length is 8191"

Argh!!! I've got websites constantly crashing and coustomers ready to
revolt, what can I do???