Thanks for getting in touch. You should be able to find your logs via 'Showing Configuration Location' (under Help menu in FrontlineSMS). When you go to the config file location you should see a folder containing your logs.
In terms of further suggestions, our Lead Developer suggested that it could be helpful for us to see a screenshot of your action config to try to work out why your experiencing this problem?
Keep us posted on how you get on, and let us know if we can be of further help.