By default, all time records that you make by submitting time from activeCollab Timer are marked as Billable. If you wish to have the option to track non-billable time, here's how you can do that:
Now save the .INI file and restart your activeCollab Timer. All timer records (on all your accounts) will be marked as Non-billable.
If you wish to enable this option again in future, just change the value of the Billable line in the .INI file from 0 to 1.