Try this:

1. Uninstall Weapon For FSX
2. Turn your Anti Virus off, or disable the shields (if you have that option).
3. Check-In to Your Profile > Select Product (Weapon [FSX]) > Extended Download Service > Get New Links
4. Download Weapon For FSX from the provided link.
5. After the download is complete, right click on the installer (csw001_1000.exe), and select "Run as Administrator" from the list.
6. After it has finished installing, go to x:\Steam\steamapps\common\FSX and find the fsx.exe file, right click on it, and select "Run as Administrator" from the list.

Once FSX-SE has started, select the Captain Sim Boeing F/A-18 Armed Defender, and any start location you want. When it is ready to fly, press Shift+1 to see if the Weapon Control Panel pops up.

Hopefully it will be working correctly.