Simplest install fails

[paultanner]

After a recent reboot of the Pi on which I run emonhub it would not start.
I decided to reinstall 'stable' from scratch following the instructions on the index page. This fails because I do not have /opt/openenergymonitor/emonhub/conf/available.conf

I use my (original) very simple config as follows:
This is just to post the output of my Sontex to MQTT.

[hub]
### loglevel must be one of DEBUG, INFO, WARNING, ERROR, and CRITICAL
loglevel = ERROR ##DEBUG
### Uncomment this to also send to syslog
# use_syslog = yes

[interfacers]

[[MQTT]]
    Type = EmonHubMqttInterfacer
        [[[init_settings]]]
            mqtt_host = 127.0.0.1
            mqtt_port = 1883
            mqtt_user = emonpi
            mqtt_passwd = emonpimqtt2023
        [[[runtimesettings]]]
             subchannels = ToEmonCMS,
             pubchannels = emon/CHANNEL1,
             timestamped = True

[[MBUS]]
    Type = EmonHubMBUSInterfacer
    [[[init_settings]]]
        device = /dev/ttyAMA0
        baud = 2400
    [[[runtimesettings]]]
        pubchannels = ToEmonCMS,
        read_interval = 60
        validate_checksum = False
        nodename = heatmeter
        [[[[meters]]]]
            [[[[[heatmeter]]]]]
                address = 1
                type = sontex531

[nodes]

This throws the following on restarting the service

Jan 27 15:18:11 pi5 systemd[1]: Starting emonHub data multiplexer...
Jan 27 15:18:11 pi5 systemd[1]: Started emonHub data multiplexer.
Jan 27 15:18:12 pi5 emonhub[10811]: Unable to load available.conf

AFAIK I do not need any nodes (did not until this latest reboot anyway)

[paultanner]

Deleted and reinstalled emonhub (v2.7.2) from scratch.

Now says
ERROR MainThread Could not open serial port: /dev/ttyUSB0 @ 115200 bits/s (retry every 10s)
ERROR MainThread Could not connect to RFM69 module
WARNING MainThread Setting emoncmsorg apikey: obscured

As above, I am giving the com port as /dev/ttyAMA0 (which does exist)
An RFM69 module is not referenced in my config
There is no [[emoncmsorg]] in my conf so why is it complaining about a lack of apikey?

Help pls.