As an alternative option that might help you, I've written a python script designed to monitor for external IP address changes. Since it's python it should work on Windows just fine after setting up the appropriate Python environment (although I've only tested it under Linux). It currently saves the "current" external IP address to a file and, when run, grabs a new IP address and then checks it against the old one. It is design to email you with this change.
It's designed to run as a cronjob (Linux) or scheduled task (Windows) and does not run as a background daemon on its own.
Here's the link to the github repository: https://github.com/begleysm/ipwatch
Hopefully it helps!