I'm sorry for the delay. We had to include a fix in the preview in order to import memory dumps on a machine with SP1 from a machine without SP1 (for some reason the Microsoft Debugging Tools expects a version string like "4.0.30319.01" instead of "4.0.30319.1"). I was hoping that we would be able to create a new version for you before replying to your post, but we still have some testing to do. Hopefully the updated preview will be available for download tomorrow.
Anyway, to import the memory dump you will need the correct mscordacwks.dll file. You can copy it from the machine where the memory dump was created. Unfortunately, this file is not available from the Microsoft symbol servers (not all versions are).
SciTech Software AB