The first thing I would recommend is to make some changes to the block definition. Currently the insertion point is very far away from the geometry, and it has an atypical rotation. Something like the below will make it much easier to work with.
With that setup, then you can draw a circle centered at the first rotation point that passes through the second point. Intersect that circle with the path curve, and you have the two points that you need to define the rotation of the block reference.
Hope that helps!
BlockRotate.dyn (47.4 KB)
TemplateRotate.dwg (901.5 KB)