If the NinjaTrader Toolkit Installer won't run on your computer for some reason, a complete uninstall and reinstall may help. Here's how you do it:
Step 1. In windows explorer, type the following address: %localappdata%/Apps and then press Enter. (You can copy and paste it from here if you like)
Step 2. In the location that appears, find the folder named 2.0 and delete it. This effectively uninstalls the toolkit and any other click-once applications on your computer.
Step 3. Restart the Apex Investing Toolkit for NinjaTrader. You can do that by clicking the red icon on your desktop if there is one, or by downloading and running this file: Toolkit