I was having the same problem, and found the inc_features.php includes " AND p.cat != 500" in the SELECT statements. If you've only got member galleries and no other categories then you get an empty result set.
Now, why does the Featured Photos panel on this site include member galleries (cat=500)? And why is the above AND included in the distributed code?
Not meaning to offend anyone, but the documentation on photopost is very poor and invariably requires a lot of digging around, and there's a lot of information still on this site that is extremely outdated, and some that is simply wrong e.g. in the upgrade instructions for 4.8.5...
2) From the upgrades directory, upload the script upgrade482.php (if you have an earlier version, you may need to upload other upgrade scripts) to your main PhotoPost directory. Run the upgrade482.php script to perform the upgrade.
What upgrades directory? There isn't one in the downloaded archive! OK, upgrade.txt in the archive has the correct instruction. And what if you have 4.8d? After some digging I figured there were no database changes from 4.8d to 4.8.2 so used the 4.8.2 upgrade script...but it was by no means obvious.
Sorry for the digression.