Prevent bind to ipv6?

[snhirsch]

I'm getting these ugly messages at startup:

INFO: conn_add_tcp: Creating TCP listener on port 5816.
INFO: adaptor_event_loop: [/dev/ttyUSB0] Connection starting.
INFO: conn_create_common: [IPv4-5816] Using '/home/hirsch/nabu/nhacp' for local storage.
INFO: image_channel_select: [IPv4-5816] Selected channel 1 (nabu on Local).
ERROR: conn_add_tcp: Unable to bind IPv6-5816: Address already in use
mj_string_size: weird type 9
mj_snprint: weird type 9
ERROR: config_error: Invalid Connection object.:

How can I prevent nabud from attempting to use IPv6 ports?