[Spikedude]

My best guesses are the two things already stated: The folder that you have the ganis in isn't listed in your folder configuration (and therefore is being skipped by the server when the player downloads files at login) or the image isn't uploaded on the server (though the gani would still play in this case, only without the sprites that aren't online). You could also potentially be setting the gani wrong, such as setting your own gani in a clientside script (which would only change the state of your character on YOUR client and not the rest of the server).

A final guess; where you're calling the setAni() function, don't put ".gani" in the filename. For a gani named "this_gani-idle.gani" you'd have a script that says "setAni("this_gani-idle",null);"