Dear nicolelee:
I just had the same problem and realized that we have to do the following:
1. Give file permissions to the folder /upcoming to be able to write on it.
2. In the upcoming.php file look at the line (~35)
define (‘UPCOMING_CACHE_PATH’, ‘/wp-content/plugins/upcoming/’);
You must give the full physical path. In my case I needed to put, instead of ‘/wp-content/plugins/upcoming/’ a path like: ‘D:\\inetpub\\mywebsitename\\wp-content\\plugins\\upcoming\\’ and it worked.
Notice the double \\.
Hope this helps.
