There are a few recommended troubleshooting steps to alleviate this:
1. The best practice is to install without an existing Tomcat implementation. Verify whether Tomcat is currently installed on this PC. If so, uninstall Tomcat and run the installer again.
2. Assign a different port for the servlet engine. This can be changed within the server.xml file located here:
3. If the installer has stopped at approximately 90% complete, and 5 minutes have elapsed, start the ThingWorx Servlet Engine Service manually from this directory in the Windows Explorer:
4. The Servlet Engine log files can be used for advanced troubleshooting. They are located in this directory by default: