dlearious: I had the same issue, i think after some research that you have to use the page up and page down key to raise the cursor above ground level to actually move it. Can't get the game to run though, so let me know if this works.
Hello, I encountered the same problem; the landspeeder simply won't move. I tried with page up/page down but to no avail. The fact is, even in the FAQ/Walkthrough you can download from GameFAQs you can read "Now I don't know if this happens to anyone else's game but in mine the Landspeeder can't move!!!!", so I'm beginning to wonder if it's actually a bug more than anything else...
(BTW I had the same issue with the Dreadnought in mission 12. At some point it refused to move again - it had suffered no hit up to then. I ended up losing it because of this)