Looks like you have followed a different link to upload the plugin to WordPress. Please follow instructions below.
1) Download the plugin (.zip file) using the link sent to your email.
2) Try to open the zip file with your zip file opener to just see if the file is intact and not corrupted.
3) Disable the free version of announcer plugin.
3) Navigate to the plugin upload page and upload the PRO version.
See this youtube video.
4) Activate the plugin. If you continue to receive the same error for some reason, please send the username and password of your staging site to my contact form below. I’ll check it out live.