Inheritance has some odd issues resulting in "unexpected errors".
To reproduce:
Make a three-deep class hierarchy.
Instantiate an instance of the lowest child class.
Call a method of the object's first parent class.
Result: Unexpected error.
Additionally:
Create three classes. Make the third a subclass of the second, but leave the first unrelated to the other two.
Create an instance of the third class.
Call a method from the parent class.
Result: Unexpected error.
Relevant forum post:
http://toolkitzone.com/forum/viewtopic.php?t=44202&postdays=0&postorder=asc&start=10#495200
See the attached file for example code.
Code for reproducing the described bugs