A subtle change to Apple System Profiler 1.3.1 version, was the change in file type from APPL to APPD. This was done to facilitate auto routing to the Apple Menu Items folder when the application is dropped onto the System Folder.
This different file type causes some confusion under At Ease when launching the application. Mac Easy Open gets involved thinking this is a document instead of an application and produces the problem error message.
If an older version of Apple System Profiler (of file type APPL) is also present on the disk, then Mac Easy Open launches this application and tells it to open the APPD version of Apple System Profiler, producing a blank window, whose name is the same as the Apple System Profiler (APPD) application.
For now, a work around is to use any file type changing utility, (ResEdit, DiskTop, Drop?Info, FileBuddy, FileTyper) to change the file type of Apple System Profiler to APPL.
This problem is fixed in ANAT 2.0 (At Ease 5.0).