Both bds.exe are untampered as far as I can tell and work in the admin account but not in the dev account.
10.2 gives a fault similar to Seans Observation but states a problem with ntdll.dll.
XE2 does not give a sound or a fault at all, it just dies silently with no error (log).
Repair used to be a great thing to get it up and running but gets halted infinitely because of no access to the network resource /bin.
The problem seems to have started with the installation of 10.2. Afterwards XE2 would only start with -rfoo after each start of 10.2.
Since todays Windows Update both installations are dead.