This error message occurs when you access photo folders containing apostrophe ’ in the folder name under [Photo] tab → View by album . But you can still access these photos via the [All] tab.
This is obviously a bug, which needs to be fixed in the future release.
The original post refers to a different version of the app that is a year and a half older than the one you are using. Did you try following the recommendations in that thread? Does this happen in another iOS device at your disposal?
I just like to share my finding to others encountered the same issue. Since I just started using this app from a few days ago, I only tested on v4.4.4 and v4.4.5, both exhibit the same behaviour on various iOS devices including iPad / iPad mini / iPhone.
The solution is to delete apostrophe in the folder name.
I have some folders with apostrophes, but I don’t upload to them ,e.g., I upload all Camera Roll content to a folder named My New Uploads, and from there I move the photos and videos to Mike’s Photos or Mike’s Videos. Try something like this to avoid uploading to folders with apostrophes.