Each archive for 3ds Max version 8 and below contains a single plug-in file – Ky_MilkyWay.dlv.
Each archive for 3ds Max version 9 and above contains two plug-in files – Ky_MilkyWay.dlv, one for 32-bit and 64-bit version of 3ds Max in a folders named 32-bit and 64-bit respectively.
If the plug-in Ky_Milky Way has been already installed in 3ds Max, then you must delete / overwrite the old plug-in file. Otherwise, during loading 3ds Max, the error message will be displayed: "Error Loading DLLs. Class ... from ... has duplicate class ID: not loading."