I'm not sure to fully understand the reason of your request:
- You have a crash in g3d.dll that happens ONLY after you install the Wilco airplane.
- You remove the Wilco airplane and the crash goes away.
- You reinstall the FSDT products and they work normally.
Are you sure this question belongs here
Even if this is not an FSDT support question, a possible reason is that maybe the Wilco airplane comes with FSUIPC, which in recent versions has a feature that prevents lots of g3d.dll errors, but the version that comes with the Wilco is older and doesn't have that feature so, the Wilco installer has downgraded your FSUIPC.
Try to do the following in this order:
1) Reinstall the Wilco airplane
2) Download the very latest FSUIPC and install it
3) Download and install the Stand-Alone Addon Manager, as the last thing you do, just to be sure everything's updated on our side.