Hey Zeustaik,
It sounds like you are trying to reference the first blueprint’s class, not a placed version of the blueprint in your level.
This section from our documentation should get you back on the right track: https://docs.unrealengine.com/latest/INT/Engine/Blueprints/UserGuide/BlueprintComms/index.html
Let us know if you are still having trouble with your implementation.
Thanks,
-Steve