Ah, that old "Run as Administrator" thing. It's such a habit for me in Win 7 that I forget about it.
It is interesting that your synth list has the "Shared DXi" heading - mine doesn't. In the Plug-In Manager, it does show up in the DXi category, though, along with TTS-1, Cyclone, GroovePlayer, PSYN II, and Roland GrooveSynth. And they are grouped together in the insert synth list, there's just no heading describing them as DXis.
On the other hand, Pentagon I doesn't appear in the VST category in the Plug-In Manager, so maybe the VST version wasn't included in X2, or if it was, there's some trick to get it to appear.