Assertion failure in walreceiver

I tried to set up a simple master/slave setup and immediately ran into
this assertion failure. The slave is just a cold copy of the database
immediately after initdb. The first WAL segment hasn't been archived
yet. It sees that the first archive fail hasn't been archived yet,
starts up walreceiver but it looks like the start point hasn't been
initialized yet because it hasn't processed any checkpoint WAL records
yet.

$ /usr/local/pgsql/bin/postgres -D /var/tmp/pg85/s/
LOG: database system was shut down at 2010-02-23 14:30:08 GMT
cp: cannot stat `/var/tmp/pg85/w/000000010000000000000000': No such
file or directory
TRAP: FailedAssertion("!(startpoint.xlogid != 0 || startpoint.xrecoff
!= 0)", File: "libpqwalreceiver.c", Line: 87)
LOG: WAL receiver process (PID 3536) was terminated by signal 6: Aborted
LOG: terminating any other active server processes
LOG: startup process (PID 3534) exited with exit code 2
LOG: aborting startup due to startup process failure

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greg