The disabled options have me confused?
- Change the source file (from the original .avi you selected)
- Change the starting point (say start at 30 seconds)
I can see that those toolbar options are disabled (below) but I cannot see the reason.

Figure: Why can’t I ‘Trim Video’ but others can http://www.dkszone.net/how-to-embed-format-and-edit-videos-in

Figure: Why are these options in the toolbar disabled?