Verify that the Tox4Upgd.exe file is in the same location as is set in the Toxicall.ini file for the AutoUpgradeFile parameter. The path must be entered exactly or this feature will not work.
If the TOXICALL® installation process is asking the user to select a path for the install, check the AutoUpgradePrompt parameter in the TOXICALL® file. It should be set to 0, if it should automatically upgrade without user input.