Did pg_dumpall and imported, NEED TO START OVER

I'm using v7.4

I created a blank .7.4 to import a pg_dumpall  into.  (Also a v8.2 to upgrade to.)

The encoding was wrong and I have a lot of:

   psql:/tmp/cluster_pg_dumpall.txt:4382: ERROR:  invalid byte sequence for encoding "UTF8": 0x91

   HINT:  This error can also happen if the byte sequence does not match the encoding expected by the server, which is controlled by "client_encoding".

   CONTEXT:  COPY brokenbin, line 443

Do I have to back out and start over?

drop database?

Or clear out and start over w/ a new install?

If the latter, what do I drop before I can start over w/ an `initdb -E SQL_ASCII`

THANKS!