Both Land_4 and Land_and_Buggy_2 have a setup() method, so I suppose they are actually two different sketches using the same classes, or something like that. Separate the sketches, duplicate the classes and see if it works better.

Thanks for the reply PhiLho,
You could kindly give me an example of what I should change?

Many thanks

Remove the following files from the download:

• Land_and_Buggy_2.java
• Land_and_Buggy_2.pde
• Land2D.pde
• /code folder