Try setting the coordinate space to World (GetLocationAtDistance). Those actors are not relative to the spline’s owner.
I believe they are spawning, just not where you can see them. Knowing the template’s coords, it’s likely they’re behind that wall (the local coords you’re feeding are close to 100,0,0 or thereabout):
You can bump their scale or Draw Debug String at that location to see where it is, in case it’s embedded in level geometry.