Thanks for replying. I tried redownloading but was facing the same error. So, I tried searching online and found this. Starting Mudlet as administrator fixed the error.

Hello everyone. I am unable to install Mudlet 4.10.1 On Windows 10 PC. Every time I am trying to install the application, it shows the “Error Opening File For Writing” message. I don’t know why this happening and how to fix it. If anyone provides any suggestions would be greatly appreciated.