Does the fx tool and the object placement tool work? The fx tool should show up in a Tools menu (like the traffic toolbox should).
I don't expect they do as they refer to the C:Program Files directory and not the C:Program Files (x86) directory. In fact, only the last entry points to a valid location. Everything else points to the C:Program Files directory which is for 64bit programs only (FSX and SDK are 32bit only so they appear only in the (x86) dir).
Open up your dll.xml and replace everything with the following (you can make a backup first of your original if you like):
<?xml version="1.0" encoding="Windows-1252"?>
<SimBase.Document Type="Launch" version="1,0">
<Path>..\Microsoft Flight Simulator X SDK\SDK\Environment Kit\Traffic Toolbox SDK\traffictoolbox.dll</Path>
This is basically the text from the SDK but the SDK has a couple of "-"s in funny places which may cause problems.
Also, be sure you have the most up to date SDK installed. If you have the original FSX version then you need to install the SDK and then both updates (you have to install both, one after the other). If you have Gold or Acceleration, again, check you have the SDK up to date.