Hi Jason -
Lots of sympathy, mate, FSUIPC drove me nuts too, but it is worth persevering with.
Groundwork first:
Start FS9, go to Settings, and untick "Enable Joystick" That will stop Windows interfering with what you are trying to do. Click OK to exit FS.
Install FSUIPC and register it ( IIRC you get a choice about registering it later).
Make sure you only have ONE instance of fsuipc.dll on the machine, and that it is in the FS9\Modules folder. If you want to keep a copy, keep it externally, on a USB stick or whatever. You can leave the setup exe on the machine without causing probs.
Go back into FS9, create a flight. Use Alt to bring up the menu bar, open Modules>FSUIPC to get the dialog box.
Now, there is no Apply button in FSUIPC - it remembers what you set - so don't click OK either or you will soon be climbing the walls, because it kicks you out when you say OK.
Click the "Axis Assignment"tab. It may or may not show you something at this stage. The trick is to click Rescan until it gives up and shows 'MOVE LEVER'. Then you move the lever of your choice for throttle #1. The display will show you some numbers moving, and also which axis you are working on. I like to note that down.
At the left side of the dialog box:
Click the "Send direct to FSUIPC..." radio button.
Check the box for the first row of the four fields, then open the pulldown by clicking the little triangle pointer on the button at the other end of the row. Select Throttle 1 from the list.
Now click the Rescan button as before and when it says Move lever, move your choice for Throttle #2, and so on.
When you have four levers assigned, click on the Joystick Calibration tab. At top centre of the dialog box, there is a field with Forward/Back buttons. Click the RH one until you get to 'Separate Throttles (page 3 of 11)'. You will then see four small panels, one for each throttle. Start with Throttle 1, check the Filter box (this reduces spikes and allows more precise setting) then work the lever a few times from fully closed to fully open. you should see +16384 for fully open and -16384 for closed. Click "Set" for that throttle, and repeat for the other three.
You don't need to "Map 1 > 1 & 2" etc because you are setting up four throttles.
You can reopen the Axis Assignment tab and use the same process for your Mixture and Prop Pitch levers, or you might want to leave that for now.
Now at long last you can click OK and you will have levers that make the engines make the right noise. You will probably want to map the detent positions, especially for Mixture and Prop Pitch. That is a bit fiddly but if you have managed this basic 'learn-to-drive-FSUIPC' I don't think you will have much trouble. At least the User's Guide will make more sense than it does at first.
Hope this helps
ATB
MikeW