By default, ExtendSim opens the Getting Started model when it launches. That model uses the RightClickConnect database, which calls the ExtendSim_DB_Connector DLL. The installer for ExtendSim needs to register that DLL in the Windows Registry during installation. The error message indicates that your system has blocked the ExtendSim installer from registering the DLL.

• Right-click the ExtendSim application and select Run as Administrator. Or contact your IT or Admin and have them launch ExtendSim (in your user account) with the correct Admin permissions (once that happens, it won’t be required again).
• If that doesn’t fix the problem, install ExtendSim again with your virus protection software temporarily disabled.