When using two forms on the same page the autocomplete function only works on the first form. Even when only using autocomplete on the second form it does not work.
After the first form has been displayed (with or without autocomplete) the initcode that loads javascript [autocomplete.js] and the initcode of the array is never there.
Only when completely removing the first form the second form will work properly.
Thanks for using FormHandler. I've tested your code and discovered the same bug. It's caused by a static variable $return in the function "getJavascriptCode" in class.FormHandler.php.
Removing the keyword static will correct this bug, I'll discuss the change with my collegue because it won't be there without a reason ;)