Postgres incomplete startup packet error

I am attempting to install Postgres 9.3 on Ubuntu 14.04 and I am getting an irksome error on startup. Here's what I'm seeing:

$ sudo service postgresql restart
* Restarting PostgreSQL 9.3 database server
* Error: could not exec /usr/lib/postgresql/9.3/bin/pg_ctl /usr/lib/postgresql/9.3/bin/pg_ctl start -D /var/lib/postgresql/9.3/main -l /var/log/postgresql/postgresql-9.3-main.log -s -o  -c config_file="/etc/postgresql/9.3/main/postgresql.conf" : [fail]

So I checked the log file with this output:

2015-01-05 21:50:05 EST LOG:  database system was shut down at 2015-01-05 21:50:03 EST
 2015-01-05 21:50:05 EST LOG:  database system is ready to accept connections
 2015-01-05 21:50:05 EST LOG:  autovacuum launcher started
 2015-01-05 21:50:06 EST LOG:  incomplete startup packet
 2015-01-05 21:51:22 EST ERROR:  syntax error at or near "exit" at character 1
 2015-01-05 21:51:22 EST STATEMENT:  exit;

"Incomplete startup packet" seems to be the culprit but I am having trouble finding info out there on what might be going on, so I thought I would ask. Thanks in advance.

There are 3 different items in this question:

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Incomplete startup packet occuring at server start is inconsequential, you may ignore it. Read Incomplete startup packet help needed (in pgsql-general mailing-list) for more.

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syntax error at or near "exit" at character 1 means that a client issued exit as if it was an SQL statement.

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The could not exec error when issuing service postgresql restart looks like a serious installation problem but it's contradicted by the log entry database system is ready to accept connections meaning that the server started up just fine.

StackExchange Database Administrators Q#87622, answer score: 24