Some trouble shooting techniques are in order to determine the source of the problem. It could be the element, your vehicle, your file or your settings. To isolate the problem try the following
1) Test on a new element
2) Test with different vehicles or a different vehicle library
3) Test in a new clean file
4) Test with a different workspace
5) Test on a different computer
If all else fails, post your file and let others have a look at it.