Error at startup

I'm running Postgres 7.2 on Debian Sid.  I've been hitting the
database all day long without problem.  This evening I added an IP
address to my pg_hba.conf, to allow an ODBC connection.  When I
tried a restart to run the new config, the server failed to start
giving an error of "Unknown ID: -" and nothing else.  Nothing in the
log.  I removed the line I had just added, putting my pg_hba.conf
file back to where it was before, and it still won't start.  Fails
with the same error.  Can anyone tell me what this error might be
indicating??  I could not find it in the docs.

Thanks in advance!
jdk