I'm trying to upgrade, but I cannot uninstall the previous version

As of v2.4, when upgrading Drive Bender, you need to uninstall any previous version before you can install the newer version (see https://divisionm.zendesk.com/knowledge/articles/214025563)

If you receive an error when uninstalling a previous version, you can force an in-place upgrade by simply removing the Drive Bender driver, then performing a re-install.

1) Using the Driver Utility (under the Drive Bender Start menu), uninstall the current driver.
2) Reboot, then you should be able to start the newer installer.