Form bind error when running Ant script

Hi

I have an IntelliJ project with some GUI designer forms which all build and run properly from within the IDE, but when I generate an Ant build, I get the following error :

BUILD FAILED
/my_file.xml:1687: /my_path/AaForm.form: The form is bound to the class my_package.AaForm.
Another form /my_path/AaForm.form is also bound to this class.

I would guess it is trying to bind the form twice. So I tried making another java class, and rebinding the form to it, and got:

BUILD FAILED
/my_file.xml:1687: /my_path/AaForm.form: The form is bound to the class my_package.DummyForm.
Another form /my_path/AaForm.form is also bound to this class.

Any ideas on what is going wrong?