"Guests aren't going into walkthrough enclosures!"

    Because of how the game works, guests won't be attracted to walkthrough exhibits without incentive to come inside (animals alone won't cut it, guests are unable to view animals they share a space with from paths). In tandem with the newly-added guest gates and exhibit paths, you should also put viewing aids like benches and viewing canopies, as well as things like amenities to further coax the guests into coming inside.

"Certain things aren't showing up!" or "Things aren't working properly!"

    Odds are that you have other mods installed that are conflicting with Folksy Facelift. Zoo Tycoon 2: Folksy Facelift was designed solely as a patch for the vanilla game in mind and edits a lot of things, so if you have it installed alongside other mods that change just about anything in the vanilla game (especially when those things involve animal changes, new maps or UI or lang changes), odds are that lots of clashing will occur. Not every mod will war with Folksy Facelift, mind; I've heard that Artifex's mods (Arabian Nights and Island Excursions) don't clash with it too much, and personally speaking, having Thom's Cheat Codes mod installed during development really helped things along.

Zoo Tycoon 2 mods work in a sort of hierarchy system - sorted by name, the further a mod is down the list of files, the more priority it has when the game loads up. With most mods, the most common way to negate this is to add lots of Z's to the front of a file - e.g. changing the name of "MyMod.z2f" to "zzzzzzMyMod.z2f". This fix should work fine with manual installs but may cause issues if you installed Folksy Facelift with the installer (like not updating properly or fully uninstalling) necessitating manual removal of the main .z2f. If you have used the installer to download Folksy Facelift and would like to use the Z trick with it, make sure you remove all of the z's before updating or uninstalling it.

"The sizes of pre-placed animals in campaigns and old save files are strange."

    If an animal is placed in a zoo and the game is saved, that animal's size is saved along with all of its other traits and everything else about the zoo; this means they won't automatically update to account for all of the changes to animals' sizes that Folksy Facelift makes. Though the campaigns could be edited to account for all of this, this would both be extremely tedious to carry out and would make the file size for the mod exponentially larger - the game can only handle so much user content. Perhaps an optional patch to fix this issue could be released one day...

"The new maps aren't appearing!"

    I wish I knew what causes this for some players, but this is an issue that some players report with Folksy Facelift despite them usually working fine with other players. I can't say for certain but I believe clashing mods is a factor. There might also be some incompatability with non-Ultimate Collection versions of the game at play. Either way, this isn't something I can fix.

"Why does Folksy Facelift not include any new biomes?"

This isn't a problem, but it is a question that crops up a good bit. There are two reasons for this, but the main one is that Zoo Tycoon 2 isn't built to accomodate any more biomes than the ones Blue Fang included in the base game and later added in Marine Mania. It's impossible to edit things like challenges and campaigns to account for usermade ones - if animals like the Asian elephant and Bengal tiger were moved to a new Dry Forest biome, they would be useless nuisances in scenarios like "The World's Biomes", taking adoption slots from animals that could actually progress the scenario.

The second reason is more subjective, I think most of them are redundant and already covered by existing biomes. Pulling examples from a certain realism-focused mega-mod, Tropical Dry Forest can easily be substituted with Tropical Rainforest (there's a lot of animal overlap anyway) and regular Temperate Forest makes a Temperate Rainforest biome unnecessary. That's not even getting into particularly brainless "biomes" like Freshwater, which serves as an all-encompassing, overstuffed blanket for animals, strictly aquatic or otherwise, that could (and really should) go in the other biomes.