If you removed the @Override annotation and that fixes your compilation problem, then that means you didn't properly override the actionPerformed method. In this case, there are a few things to check:
1. Did you remember to have your class extend/implement some class/interface?
2. Is the method spelled correctly (Java is case-sensitive)?
3. Do you have the parameters correct (both type and order matter, name not so much)?
4. Do you have at least the access level defined in the superclass? This means that if a method was declared protected in the super class, it must be protected or public in your class?