Thanks to a lot of work by Larry Cowan, assisted by Dave Menzies, a current Nation Checklist Add-On is now available. This file is updated as of Nov 24, 2016. This is now a free download that can be used by anybody; you do not need to have previously purchased the Add-On.
To install the update, download the RANGES.zip file, unzip RANGES.LST from it, and place RANGES.LST in your DATA folder (and restart AviSys if you already have it running). That's all you have to do!
If you have not previously had the Add-On installed, the one visible difference that you will observe is that the button that used to be labeled “StateCL” will now be labeled “Range”. When you click the Range button, the same State Checklist Status window opens, but its “Nations” button will be clickable. Clicking the Nations button will display the nations in which the selected species occurs. Unlike the states list, this nations list is not editable.
With RANGES.LST installed, you will be able to create a checklist for any nation (although note that AviSys is locked into identifying nations by old names, some of which are obsolete—this cannot be fixed). To add a checklist for a nation, open the Checklists menu, click Add, then click Add again on the next dialog, then select the nation that you want and click OK, and then click OK again.
If you should ever decide that you don't want the Add-On installed, simply delete RANGES.LST from your data folder.
Current revision date of RANGES.LST: April 30, 2017.