JB,
I'm curious if you'll run into the same issue if you download and install the standalone 32-bit Exchange tools found here:
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=6be38633-7248-4532-929b-76e9c677e802&displaylang=en
You'll notice that there are three options for the download. They're basically just versions to match the service pack of Exchange you have installed (SP1-SP3). Choose to do a custom install, and only check the box next to the tools (bottom option if I remember correctly).
Let us know if this makes any difference.
To answer your other questions, you are correct that the 7.0 versions of our products only install on Server 2003 (32-bit). The 7.1 product line (due in March) will move to Server 2008 R2 64-bit only. We do not have a version of Mobile that will run on the 7.1 Platform today, and we won't likely have one until the June/July timeframe as we are devoting all of our resources in to 7.0 SP4 (native support for iOS devices) and SP5 (native support for Android devices).
Brian