To manually register on a Windows x64 version you have to use regsvr32.exe from %systemroot%\System32\regsvr32.exe
For example :
%systemroot%\System32\regsvr32.exe C:\Windows\System32\webpext64.dll
C:\Windows\SysWOW64\regsvr32.exe /u C:\Where\The\Dll\Resides\webpext64.dll is for Windows x86 .
source: https://support.microsoft.com/en-us/topic/how-to-use-the-regsvr32-tool-and-troubleshoot-regsvr32-error-messages-a98d960a-7392-e6fe-d90a-3f4e0cb543e5 (How to use the Regsvr32 tool and troubleshoot Regsvr32 error messages)
To manually register on a Windows x64 version you have to use regsvr32.exe from %systemroot%\System32\regsvr32.exe
For example :
%systemroot%\System32\regsvr32.exe C:\Windows\System32\webpext64.dll
C:\Windows\SysWOW64\regsvr32.exe /u C:\Where\The\Dll\Resides\webpext64.dll is for Windows x86 .
source: https://support.microsoft.com/en-us/topic/how-to-use-the-regsvr32-tool-and-troubleshoot-regsvr32-error-messages-a98d960a-7392-e6fe-d90a-3f4e0cb543e5 (How to use the Regsvr32 tool and troubleshoot Regsvr32 error messages)