If the largest of the 4 Community Builder extensions won't upload and you keep getting an unspecified error message, try this.
1. Create a file named phpinfo.php in your main directory with this and only this in the file:
<?php phpinfo() ; ?>
2. Upload the file to the main directory.
3. Go to your site and access that file. For example, one of my sites is http://www.ethancastanon.com
If I were to have uploaded the file to my main directory, I would then access it by typing this in my web browser's address line: http://www.ethancastanon.com/phpinfo.php
4. Search for "upload_max_filesize." Check if it's set at 2M.
5. If it's set at 2M or below, check if there is a php.ini file in your main directory.
6. If there isn't, create one with this line and only this line in it: upload_max_filesize = 10M. Again name this file php.ini
7. Try uploading the last Community Builder extension.
8. If it works, you will see this: