I downloaded one of your templates and the only changes I have made are the images, a line of text and the heading and link tags. I zipped up the file with the index page, images and css files all included and tried to import it as a campaign - however I can't upload it and keep getting the error message 'html file field must not be empty'. Why I am getting this error message and what does it mean? The html file from the original template is in the zipped file and is still called 'index' so I don't understand why this isn't working....
That sounds like a strange one, and to be honest I can't say I've heard of that problem before. What browser are you using?
Just to make sure as well, in step 2.2 you are choosing to "Import the campaign from my computer or network" and then on step 2.3, you are first only selecting the .html file for "The HTML page" and then selecting the .zip for the "All other files in zip format (optional)" selection, choosing the .zip?