the way you are using the LoadSprite() command it's using "mesh" as a texture flag, not as the parent.
LoadSprite ( tex_file$[,tex_flag][,parent] )
It may work in debug mode because whatever screen settings debug mode uses, the incorrect flag may work ok, or may be ignored completely.
Try using LoadSprite("fire.bmp",1,mesh)
or
Global flare=LoadSprite("fire.bmp")
EntityParent flare,mesh
(edited for clarity)
LoadSprite ( tex_file$[,tex_flag][,parent] )
It may work in debug mode because whatever screen settings debug mode uses, the incorrect flag may work ok, or may be ignored completely.
Try using LoadSprite("fire.bmp",1,mesh)
or
Global flare=LoadSprite("fire.bmp")
EntityParent flare,mesh
(edited for clarity)