Getting error while uploading a template

I am getting this error why trying to upload an Unbounce template. Theme Preview There was an error unzipping the provided zip file: Please who has a solution for this?

make sure your preview image is 590x300 pixels and named 01_<filename>.jpg then just zip only the image not the image folder. Also use a popular zip software (as like winrar) to make a zip.

solved, thanks