A3 opening existing file "auto-loop"

[INFO]: LV2: Discovering 952 plugins
[WARNING]: Ignoring invalid LV2 plugin http://home.gna.org/lv2vocoder/1
[WARNING]: Ignoring invalid LV2 plugin http://miplug.in/plugins/dynamic5band/mono
[WARNING]: Ignoring invalid LV2 plugin http://miplug.in/plugins/dynamic5band/stereo
[INFO]: Loading menus from ./../build/gtk2_ardour/ardour.menus
[INFO]: Loaded mixer bindings from ./../gtk2_ardour/mixer.bindings
[ERROR]: You cannot use this location for auto-loop because it has zero or negative length
[INFO]: Loading bindings from /home/kxzu/.config/ardour3/ardour.bindings
Loading 84 MIDI patches from /home/kxzu/.config/ardour3/patchfiles:./../patchfiles:./../build/patchfiles:./../gtk2_ardour/patchfiles:./../build/gtk2_ardour/patchfiles:./patchfiles
[INFO]: Loading history from /home/kxzu/Ardour 3/trackingitwithtemplate/trackingitwithtemplate.history