I've got the same problem with "assign access control" for essbase.
Installation: default installation (incl. default ports), OS: Windows 2008 (32bit), no clustering,
EPM System Diagnostic says that everything is OK.
in my environment I get the error if I start the shared services console via the URL "http://servername:port/interop/index.jsp" and then select the "assign access control" for an essbase database (see message above).
If I start the shared services console via the workspace everything works fine.
So try this at your environment for hfm - may be it will help....
The feature, "Assign Access Control - In Shared Services Assign Access Control Module When Accessing a Financial Management Application " must work when done via the workspace URL https://bigip/workspace/index.jsp and HSS URL, https://bigip/interop/index.jsp.