I recently updated to a 64 bit box. CS3 installed fine. I donwloaded the
latest EM and installed. It gave a little trouble it actually did not finish
installing until I clicked the launch button. I then noticed some of the
extensions would not install I got an error saying I either needed a newer
version of EM or a newer version of the extension. Through trial and error I
discovered that if I re-extracted the zipped extensions on the 64 bit machine
they would install. some of the zip files were corrupt and I had to get a new
copy. Once I re-extracted them they installed and worked fine.

I hope this helps others.