
To recreate, create a new global variable in a:d 3.0.2 or later and assign it the type "string". Export to XML and use the Dialogue System import tool to import the project XML file. The console shows an error message (sorry, I'm not at my computer right now to capture it) and the project does not import successfully.
Removing the string variable allowed the import to complete without a hitch.
Thanks for an incredible program!