Help making all fields selectable

Hi,

I have created my form and sent it to a coworker to fill out as part of previewing it.  She keeps coming up with individual checkboxes and buttons that can't be selected. Im not sure why. I go in and create a new checkbox to replace the problem one and the problem persists.  Not sure what the issue is.  Thanks so much.  Also finding that other checkboxes are cropping up as unfillable.

Nicole