On each server machine, following these steps: 1. Log in as a user with admin privileges2. Copy the SOE dll to a folder accessible to the ArcGIS Server account3. Open a command prompt and go to that folder4. Execute the following command using the 64bit version of regasm. (Note: This workaround will fail if the 32bit version of regasm is used). <a href="file:C:/Windows/Microsoft.NET/Framework64/v2.0.50727/regasm.exe" target="_blank">C:\Windows\Microsoft.NET\Framework64\v2.0.50727\regasm.exe</a> <SOE.dll> /codebase