[HELP] Overgrowth atlas generation failed

Hi everyone, i'm making a new PR map but i can't generate the OvergrowthAtlas.tai file
it gives me the following error :

Ignored Warning[Overgrowth] : Overgrowth atlas generation failed
Ignored Warning[TextureAtlas] : Couldn't open TAI file "levels\alhanee\editor\tmp\OvergrowthAtlas.tai "
Ignored Warning[Overgrowth] : Overgrowth atlas generation failed
Ignored Warning[TextureAtlas] : Couldn't open TAI file "levels\alhanee\overgrowth\OvergrowthAtlas.tai "

Can someone help me ?
:S