On uploading the theme, I get “Are you sure you want to do this?”

The error “Are you sure you want to do this? Please try again.” when it occurs during theme upload, it is most likely due to a limitation on upload_max_filesize and post_max_size set by your webhost. Please contact your webhost to increase these 2 values to at least 32M. Alternatively you can use FTP to upload the theme.