How to fix the unresolved dependency in the Flag module about Flag Friend?
According to your "unresolved dependency" error messages, you are currently using the 2.2 version of the Flag module. While the Flag Friend module requires the 2.1 version of it.

It's worth trying to replacing the entire flag folder in your modules directory as follows:


backup your flag module folder (to somewhere outside your Drupal root).
delete the flag module folder and its entire content.
download the 7.x-2.1 release of the flag module and unpack that version in the very same "flag" module folder.


Then try again and see if that helps. If not restore your backup directory (to try some other approach).