Apparently the monster_osprey's origin (position) has not been set, so it's placed at the default (0, 0, 0) position. I guess Xash3D's
ent_create command will place entities at the point that you're looking at, but maybe that doesn't work correctly when you're looking at the sky, I don't know.
What happens when you use the
ent_last_origin command after creating the path_corner? What happens when you manually specify the positions (
ent_create path_corner targetname point origin "-200 -900 -1000", and
ent_create monster_osprey target point origin "-200 -900 -1000")?
If that fixes the problem, but your game crashes, then that's because the path_corner doesn't have a target. There should be no 'dead ends' in the path that the monster_osprey is following. Maybe pointing the path_corner at itself will be sufficient, but if not, then you'll need at least 2 path_corners that target each other.