If I'm understanding you correctly, you have multiple checkboxes named the same. Problem with that is that Struts will probably (correct me if I'm wrong; I'm no expert) take the last one, and set the ActionForm value to that. You need to give them different names in the JSP.
The actionForm also requires a variable for each checkbox; ie: you have three checkboxes, named checkbox1, checkbox2, and checkbox3. The actionForm then requires boolean checkbox1, boolean checkbox2, and boolean checkbox3.
Don't forget to set these to false in your reset method, since HTML has a quirky way of sending checkbox values. If it's not checked, nothing is sent for that checkbox. If it IS checked, you get data. So, the default way of handling them is to assume they're false.