Hi Paul, yeah there's a newer version that doesn't use the ActiveX Scripting.FileSystemObject, get the one that says that it's for the Mac here:
http://moi3d.com/forum/messages.php?webtag=MOI&msg=5124.2

That one uses MoI's cross-platform functions for reading the file and that one should work on both Mac and Windows v4. I think that older version may only work on MoI v1 and v2.

- Michael