problems after restoring from a pg_basebackup

Greetings,
I'm running postgresql-9.1.3 on a Linux-x86_64 (Fedora16, if it
matters) system. I noticed the existence of pg_basebackup starting in
9.1, and figured I'd try it out and see if it would simplify our
backup & management processes.

$ pg_basebackup -P -v -D /tmp/backup -x -Ft -z -U postgres
xlog start point: C6/64000020
135733616/135733616 kB (100%), 1/1 tablespace
xlog end point: C6/640000A0
pg_basebackup: base backup completed

So after running through this, I tried to use (restore) the backup
that was generated. While everything appears to be working ok from a
functional perspective, in the server log I saw the following:
######
LOG: creating missing WAL directory "pg_xlog/archive_status"
LOG: database system was not properly shut down; automatic recovery in progress
LOG: redo starts at C6/66000078
LOG: could not open file "pg_xlog/00000001000000C600000067" (log file
198, segment 103): No such file or directory
LOG: redo done at C6/660000A0
FATAL: the database system is starting up
LOG: autovacuum launcher started
LOG: database system is ready to accept connections
#####

Just to be clear, here's what I did after pg_basebackup had completed
successfully:
0) shutdown postgresql gracefully, and verified that it was fully shutdown
1) moved $PGDATA to $PGDATA.old
2) created $PGDATA as postgres user
3) extracted the basebackup tarball as postgres user
cd $PGDATA && tar xzvpf /tmp/backup/base.tar.gz
4) started postgresql up

I would have expected that I wouldn't have gotten the 'not properly
shutdown' warning, or the 'could not open file' warning by following
this process. Am I doing something wrong?

thanks