Top 5 Actionscript 3.0 mistakes

I have compiled here a list of the top 5 mistakes that I have made while programming in Actionscript 3.0 in the past half a year.

Number 5: Creating a non-constructor.

Number 4: Not initializing variables before instantiating them.

Number 3: Not knowing how to import your classes manually.    

Number 2: Assuming that you are a good speller.

Number 1: Using any code if you don't understand what it does.