If you get a system error, that's because you haven't .net framework 2.0 installed on your PC.
Download it here .
Also, following update may be applied to fix general problems with this component.
Download .
Although it's now over with Vista and later operating systems, lack of user rights under XP may prevent Modding Tools from working... especially when TDU is installed in Program Files folder.
To avoid this, be sure to always run these tools as administrator; right-click on TDU Modding Tools executable, then Run as administrator.