Try doing it manually, maybe you'll see some kind of error message that might help understanding the problem:
- Open a command prompt with admin rights, by opening the Start menu and typing CMD. You should see a "Command Prompt" icon in the search result so, don't press Enter just yet and, instead, Right-click on the "Command Prompt" icon, and select "Run as Administrator"
- If you did it correctly, a command prompt window should open so, type the following:
C:\WINDOWS\system32\regsvr32.exe /s C:\ProgramData\Esellerate\eWebControl365.dll
Press Enter and see if it tells you something.