Where to put the Explorerframe.dll:

For x86 / 32-bit:
ExplorerFrame.dll (from x86 (32 bit) folder) goes to System32 folder

For x64 / 64-bit:
ExplorerFrame.dll (from x64 (64 bit) folder) goes in System32 folder
ExplorerFrame.dll (from x86 (32 bit) folder) goes in SysWOW64 folder