Object Blueprints do not contain a world, which prevents the node from functioning.
Spawn Emitter At Location is no longer an available node in an Object Blueprint. It was available in 4.6.1 but is not in 4.7 or 4.8. Spawn Emitter Attached is still available in an Object BP.
Tested in 4.7 Preview 5 and Main (Promotable-CL-2429371).
1. Open any project
2. Create a new Object Blueprint
3. Right-click and search for Spawn Emitter
No option for Spawn Emitter At Location appears, whether Context Sensitive is enabled or not.
Head over to the existing Questions & Answers thread and let us know what's up.