I can also vouch for the Aimtrak as a quality, working product. Some may complain about a little accuracy error (compared to traditional Lightgun / CRT setups), but for a casual like me, it's fantastic.
I'm not sure about the super/ultimate sensor bar, as I don't think that came from Ultimarc, so that might be something. Similar to how the Aimtraks don't work with a Wii sensor bar, but my Wiimotes work just fine with the Ultimarc sensor bar. If the sensor preview is working OK with it, you can probably rule that out.
A few things to try:
Do the guns work correctly on the windows desktop? If so, then there's a problem in the emulator setup. If the cursor is also stuck in the corner on the destop, then there's an issue with the hardware setup.
Are the guns set up for the correct player? I ask this since there was a clean install done (probably including MAME), as well as issues of controllers getting different hardware IDs when booting. That's a whole other can of worms, and topics abound in the software forum. It's more of an issue with Windows than anything.
And finally, is the gun calibrated in the test menu of the game? Some, like Carnevil, will not work until calibrated within the game. Dunno about Area 51 off the top of my head. But if MAME's built-in cursors don't work correctly, then this is probably not the source of the issue.
You say the sensor preview and X / Y data are providing correct data. Sounds like you're halfway there. There's a guide from Ultimarc
here on setting MAME up for the guns. Make sure your mame.ini has the correct options set.